Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 886 insertions, 0 deletions

diff --git a/dom/events/Event.cpp b/dom/events/Event.cpp
new file mode 100644
index 0000000000..1ba37f0d82
--- /dev/null
+++ b/dom/events/Event.cpp
@@ -0,0 +1,886 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "AccessCheck.h"
+#include "base/basictypes.h"
+#include "ipc/IPCMessageUtils.h"
+#include "ipc/IPCMessageUtilsSpecializations.h"
+#include "mozilla/EventDispatcher.h"
+#include "mozilla/BasePrincipal.h"
+#include "mozilla/ContentEvents.h"
+#include "mozilla/DOMEventTargetHelper.h"
+#include "mozilla/EventStateManager.h"
+#include "mozilla/InternalMutationEvent.h"
+#include "mozilla/dom/Performance.h"
+#include "mozilla/dom/WorkerPrivate.h"
+#include "mozilla/MiscEvents.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/PointerLockManager.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/TextEvents.h"
+#include "mozilla/TouchEvents.h"
+#include "mozilla/ViewportUtils.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/DocumentInlines.h"
+#include "mozilla/dom/Event.h"
+#include "mozilla/dom/ShadowRoot.h"
+#include "mozilla/dom/WorkerScope.h"
+#include "mozilla/StaticPrefs_dom.h"
+#include "mozilla/SVGUtils.h"
+#include "mozilla/SVGOuterSVGFrame.h"
+#include "nsContentUtils.h"
+#include "nsCOMPtr.h"
+#include "nsDeviceContext.h"
+#include "nsError.h"
+#include "nsGlobalWindow.h"
+#include "nsIFrame.h"
+#include "nsIContent.h"
+#include "nsIContentInlines.h"
+#include "nsIScrollableFrame.h"
+#include "nsJSEnvironment.h"
+#include "nsLayoutUtils.h"
+#include "nsPIWindowRoot.h"
+#include "nsRFPService.h"
+
+namespace mozilla::dom {
+
+Event::Event(EventTarget* aOwner, nsPresContext* aPresContext,
+             WidgetEvent* aEvent) {
+  ConstructorInit(aOwner, aPresContext, aEvent);
+}
+
+Event::Event(nsPIDOMWindowInner* aParent) {
+  ConstructorInit(nsGlobalWindowInner::Cast(aParent), nullptr, nullptr);
+}
+
+void Event::ConstructorInit(EventTarget* aOwner, nsPresContext* aPresContext,
+                            WidgetEvent* aEvent) {
+  SetOwner(aOwner);
+  mIsMainThreadEvent = NS_IsMainThread();
+
+  mPrivateDataDuplicated = false;
+  mWantsPopupControlCheck = false;
+
+  if (aEvent) {
+    mEvent = aEvent;
+    mEventIsInternal = false;
+  } else {
+    mEventIsInternal = true;
+    /*
+      A derived class might want to allocate its own type of aEvent
+      (derived from WidgetEvent). To do this, it should take care to pass
+      a non-nullptr aEvent to this ctor, e.g.:
+
+        FooEvent::FooEvent(..., WidgetEvent* aEvent)
+          : Event(..., aEvent ? aEvent : new WidgetEvent())
+
+      Then, to override the mEventIsInternal assignments done by the
+      base ctor, it should do this in its own ctor:
+
+        FooEvent::FooEvent(..., WidgetEvent* aEvent)
+        ...
+        {
+          ...
+          if (aEvent) {
+            mEventIsInternal = false;
+          }
+          else {
+            mEventIsInternal = true;
+          }
+          ...
+        }
+     */
+    mEvent = new WidgetEvent(false, eVoidEvent);
+  }
+
+  InitPresContextData(aPresContext);
+}
+
+void Event::InitPresContextData(nsPresContext* aPresContext) {
+  mPresContext = aPresContext;
+  // Get the explicit original target (if it's anonymous make it null)
+  {
+    nsCOMPtr<nsIContent> content = GetTargetFromFrame();
+    mExplicitOriginalTarget = content;
+    if (content && content->IsInNativeAnonymousSubtree()) {
+      mExplicitOriginalTarget = nullptr;
+    }
+  }
+}
+
+Event::~Event() {
+  NS_ASSERT_OWNINGTHREAD(Event);
+
+  if (mEventIsInternal && mEvent) {
+    delete mEvent;
+  }
+}
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(Event)
+  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
+  NS_INTERFACE_MAP_ENTRY(nsISupports)
+  NS_INTERFACE_MAP_ENTRY(Event)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(Event)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(Event)
+
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_CLASS(Event)
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(Event)
+  if (tmp->mEventIsInternal) {
+    tmp->mEvent->mTarget = nullptr;
+    tmp->mEvent->mCurrentTarget = nullptr;
+    tmp->mEvent->mOriginalTarget = nullptr;
+    tmp->mEvent->mRelatedTarget = nullptr;
+    tmp->mEvent->mOriginalRelatedTarget = nullptr;
+    switch (tmp->mEvent->mClass) {
+      case eDragEventClass: {
+        WidgetDragEvent* dragEvent = tmp->mEvent->AsDragEvent();
+        dragEvent->mDataTransfer = nullptr;
+        break;
+      }
+      case eClipboardEventClass:
+        tmp->mEvent->AsClipboardEvent()->mClipboardData = nullptr;
+        break;
+      case eEditorInputEventClass: {
+        InternalEditorInputEvent* inputEvent =
+            tmp->mEvent->AsEditorInputEvent();
+        inputEvent->mDataTransfer = nullptr;
+        inputEvent->mTargetRanges.Clear();
+        break;
+      }
+      case eMutationEventClass:
+        tmp->mEvent->AsMutationEvent()->mRelatedNode = nullptr;
+        break;
+      default:
+        break;
+    }
+
+    if (WidgetMouseEvent* mouseEvent = tmp->mEvent->AsMouseEvent()) {
+      mouseEvent->mClickTarget = nullptr;
+    }
+  }
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mPresContext);
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mExplicitOriginalTarget);
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mOwner);
+  NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(Event)
+  if (tmp->mEventIsInternal) {
+    NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mEvent->mTarget)
+    NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mEvent->mCurrentTarget)
+    NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mEvent->mOriginalTarget)
+    NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mEvent->mRelatedTarget)
+    NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mEvent->mOriginalRelatedTarget);
+    switch (tmp->mEvent->mClass) {
+      case eDragEventClass: {
+        WidgetDragEvent* dragEvent = tmp->mEvent->AsDragEvent();
+        NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mEvent->mDataTransfer");
+        cb.NoteXPCOMChild(dragEvent->mDataTransfer);
+        break;
+      }
+      case eClipboardEventClass:
+        NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mEvent->mClipboardData");
+        cb.NoteXPCOMChild(tmp->mEvent->AsClipboardEvent()->mClipboardData);
+        break;
+      case eEditorInputEventClass:
+        NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mEvent->mDataTransfer");
+        cb.NoteXPCOMChild(tmp->mEvent->AsEditorInputEvent()->mDataTransfer);
+        NS_IMPL_CYCLE_COLLECTION_TRAVERSE(
+            mEvent->AsEditorInputEvent()->mTargetRanges);
+        break;
+      case eMutationEventClass:
+        NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mEvent->mRelatedNode");
+        cb.NoteXPCOMChild(tmp->mEvent->AsMutationEvent()->mRelatedNode);
+        break;
+      default:
+        break;
+    }
+
+    if (WidgetMouseEvent* mouseEvent = tmp->mEvent->AsMouseEvent()) {
+      NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mEvent->mClickTarget");
+      cb.NoteXPCOMChild(mouseEvent->mClickTarget);
+    }
+  }
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mPresContext)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mExplicitOriginalTarget)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mOwner)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+JSObject* Event::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) {
+  return WrapObjectInternal(aCx, aGivenProto);
+}
+
+JSObject* Event::WrapObjectInternal(JSContext* aCx,
+                                    JS::Handle<JSObject*> aGivenProto) {
+  return Event_Binding::Wrap(aCx, this, aGivenProto);
+}
+
+void Event::GetType(nsAString& aType) const {
+  GetWidgetEventType(mEvent, aType);
+}
+
+EventTarget* Event::GetTarget() const { return mEvent->GetDOMEventTarget(); }
+
+already_AddRefed<Document> Event::GetDocument() const {
+  nsCOMPtr<EventTarget> eventTarget = GetTarget();
+
+  if (!eventTarget) {
+    return nullptr;
+  }
+
+  nsCOMPtr<nsPIDOMWindowInner> win =
+      do_QueryInterface(eventTarget->GetOwnerGlobal());
+
+  if (!win) {
+    return nullptr;
+  }
+
+  nsCOMPtr<Document> doc;
+  doc = win->GetExtantDoc();
+
+  return doc.forget();
+}
+
+EventTarget* Event::GetCurrentTarget() const {
+  return mEvent->GetCurrentDOMEventTarget();
+}
+
+void Event::ComposedPath(nsTArray<RefPtr<EventTarget>>& aPath) {
+  EventDispatcher::GetComposedPathFor(mEvent, aPath);
+}
+
+//
+// Get the actual event target node (may have been retargeted for mouse events)
+//
+already_AddRefed<nsIContent> Event::GetTargetFromFrame() {
+  if (!mPresContext) {
+    return nullptr;
+  }
+
+  // Get the mTarget frame (have to get the ESM first)
+  nsIFrame* targetFrame = mPresContext->EventStateManager()->GetEventTarget();
+  if (!targetFrame) {
+    return nullptr;
+  }
+
+  // get the real content
+  nsCOMPtr<nsIContent> realEventContent;
+  targetFrame->GetContentForEvent(mEvent, getter_AddRefs(realEventContent));
+  return realEventContent.forget();
+}
+
+EventTarget* Event::GetExplicitOriginalTarget() const {
+  if (mExplicitOriginalTarget) {
+    return mExplicitOriginalTarget;
+  }
+  return GetTarget();
+}
+
+EventTarget* Event::GetOriginalTarget() const {
+  return mEvent->GetOriginalDOMEventTarget();
+}
+
+EventTarget* Event::GetComposedTarget() const {
+  EventTarget* et = GetOriginalTarget();
+  nsCOMPtr<nsIContent> content = do_QueryInterface(et);
+  if (!content) {
+    return et;
+  }
+  nsIContent* nonChrome = content->FindFirstNonChromeOnlyAccessContent();
+  return nonChrome ? static_cast<EventTarget*>(nonChrome)
+                   : static_cast<EventTarget*>(content->GetComposedDoc());
+}
+
+void Event::SetTrusted(bool aTrusted) { mEvent->mFlags.mIsTrusted = aTrusted; }
+
+bool Event::ShouldIgnoreChromeEventTargetListener() const {
+  MOZ_ASSERT(NS_IsMainThread());
+  if (!XRE_IsParentProcess()) {
+    return false;
+  }
+  if (EventTarget* currentTarget = GetCurrentTarget();
+      NS_WARN_IF(!currentTarget) || !currentTarget->IsRootWindow()) {
+    return false;
+  }
+  EventTarget* et = GetOriginalTarget();
+  if (NS_WARN_IF(!et)) {
+    return false;
+  }
+  nsIGlobalObject* global = et->GetOwnerGlobal();
+  if (NS_WARN_IF(!global)) {
+    return false;
+  }
+  nsPIDOMWindowInner* win = global->AsInnerWindow();
+  if (NS_WARN_IF(!win)) {
+    return false;
+  }
+  BrowsingContext* bc = win->GetBrowsingContext();
+  if (NS_WARN_IF(!bc)) {
+    return false;
+  }
+  // If this is a content event on an nsWindowRoot, then we also handle this in
+  // InProcessBrowserChildMessageManager, so we can ignore this event.
+  return bc->IsContent();
+}
+
+bool Event::Init(mozilla::dom::EventTarget* aGlobal) {
+  if (!mIsMainThreadEvent) {
+    return IsCurrentThreadRunningChromeWorker();
+  }
+  bool trusted = false;
+  nsCOMPtr<nsPIDOMWindowInner> w = do_QueryInterface(aGlobal);
+  if (w) {
+    nsCOMPtr<Document> d = w->GetExtantDoc();
+    if (d) {
+      trusted = nsContentUtils::IsChromeDoc(d);
+      nsPresContext* presContext = d->GetPresContext();
+      if (presContext) {
+        InitPresContextData(presContext);
+      }
+    }
+  }
+  return trusted;
+}
+
+// static
+already_AddRefed<Event> Event::Constructor(const GlobalObject& aGlobal,
+                                           const nsAString& aType,
+                                           const EventInit& aParam) {
+  nsCOMPtr<mozilla::dom::EventTarget> t =
+      do_QueryInterface(aGlobal.GetAsSupports());
+  return Constructor(t, aType, aParam);
+}
+
+// static
+already_AddRefed<Event> Event::Constructor(EventTarget* aEventTarget,
+                                           const nsAString& aType,
+                                           const EventInit& aParam) {
+  RefPtr<Event> e = new Event(aEventTarget, nullptr, nullptr);
+  bool trusted = e->Init(aEventTarget);
+  e->InitEvent(aType, aParam.mBubbles, aParam.mCancelable);
+  e->SetTrusted(trusted);
+  e->SetComposed(aParam.mComposed);
+  return e.forget();
+}
+
+uint16_t Event::EventPhase() const {
+  // Note, remember to check that this works also
+  // if or when Bug 235441 is fixed.
+  if ((mEvent->mCurrentTarget && mEvent->mCurrentTarget == mEvent->mTarget) ||
+      mEvent->mFlags.InTargetPhase()) {
+    return Event_Binding::AT_TARGET;
+  }
+  if (mEvent->mFlags.mInCapturePhase) {
+    return Event_Binding::CAPTURING_PHASE;
+  }
+  if (mEvent->mFlags.mInBubblingPhase) {
+    return Event_Binding::BUBBLING_PHASE;
+  }
+  return Event_Binding::NONE;
+}
+
+void Event::StopPropagation() { mEvent->StopPropagation(); }
+
+void Event::StopImmediatePropagation() { mEvent->StopImmediatePropagation(); }
+
+void Event::StopCrossProcessForwarding() {
+  mEvent->StopCrossProcessForwarding();
+}
+
+void Event::PreventDefault() {
+  // This method is called only from C++ code which must handle default action
+  // of this event.  So, pass true always.
+  PreventDefaultInternal(true);
+}
+
+void Event::PreventDefault(JSContext* aCx, CallerType aCallerType) {
+  // Note that at handling default action, another event may be dispatched.
+  // Then, JS in content mey be call preventDefault()
+  // even in the event is in system event group.  Therefore, don't refer
+  // mInSystemGroup here.
+  nsIPrincipal* principal =
+      mIsMainThreadEvent ? nsContentUtils::SubjectPrincipal(aCx) : nullptr;
+
+  PreventDefaultInternal(aCallerType == CallerType::System, principal);
+}
+
+void Event::PreventDefaultInternal(bool aCalledByDefaultHandler,
+                                   nsIPrincipal* aPrincipal) {
+  if (!mEvent->mFlags.mCancelable) {
+    return;
+  }
+  if (mEvent->mFlags.mInPassiveListener) {
+    nsCOMPtr<nsPIDOMWindowInner> win(do_QueryInterface(mOwner));
+    if (win) {
+      if (Document* doc = win->GetExtantDoc()) {
+        AutoTArray<nsString, 1> params;
+        GetType(*params.AppendElement());
+        doc->WarnOnceAbout(Document::ePreventDefaultFromPassiveListener, false,
+                           params);
+      }
+    }
+    return;
+  }
+
+  mEvent->PreventDefault(aCalledByDefaultHandler, aPrincipal);
+
+  if (!IsTrusted()) {
+    return;
+  }
+
+  WidgetDragEvent* dragEvent = mEvent->AsDragEvent();
+  if (!dragEvent) {
+    return;
+  }
+
+  nsIPrincipal* principal = nullptr;
+  nsCOMPtr<nsINode> node =
+      nsINode::FromEventTargetOrNull(mEvent->mCurrentTarget);
+  if (node) {
+    principal = node->NodePrincipal();
+  } else {
+    nsCOMPtr<nsIScriptObjectPrincipal> sop =
+        do_QueryInterface(mEvent->mCurrentTarget);
+    if (sop) {
+      principal = sop->GetPrincipal();
+    }
+  }
+  if (principal && !principal->IsSystemPrincipal()) {
+    dragEvent->mDefaultPreventedOnContent = true;
+  }
+}
+
+void Event::SetEventType(const nsAString& aEventTypeArg) {
+  mEvent->mSpecifiedEventTypeString.Truncate();
+  if (mIsMainThreadEvent) {
+    mEvent->mSpecifiedEventType = nsContentUtils::GetEventMessageAndAtom(
+        aEventTypeArg, mEvent->mClass, &(mEvent->mMessage));
+    mEvent->SetDefaultComposed();
+  } else {
+    mEvent->mSpecifiedEventType = NS_Atomize(u"on"_ns + aEventTypeArg);
+    mEvent->mMessage = eUnidentifiedEvent;
+    mEvent->SetComposed(aEventTypeArg);
+  }
+  mEvent->SetDefaultComposedInNativeAnonymousContent();
+}
+
+already_AddRefed<EventTarget> Event::EnsureWebAccessibleRelatedTarget(
+    EventTarget* aRelatedTarget) {
+  nsCOMPtr<EventTarget> relatedTarget = aRelatedTarget;
+  if (relatedTarget) {
+    nsIContent* content = nsIContent::FromEventTarget(relatedTarget);
+    if (content && content->ChromeOnlyAccess() &&
+        !nsContentUtils::CanAccessNativeAnon()) {
+      content = content->FindFirstNonChromeOnlyAccessContent();
+      relatedTarget = content;
+    }
+
+    if (relatedTarget) {
+      relatedTarget = relatedTarget->GetTargetForDOMEvent();
+    }
+  }
+  return relatedTarget.forget();
+}
+
+void Event::InitEvent(const nsAString& aEventTypeArg,
+                      mozilla::CanBubble aCanBubbleArg,
+                      mozilla::Cancelable aCancelableArg,
+                      mozilla::Composed aComposedArg) {
+  // Make sure this event isn't already being dispatched.
+  NS_ENSURE_TRUE_VOID(!mEvent->mFlags.mIsBeingDispatched);
+
+  if (IsTrusted()) {
+    // Ensure the caller is permitted to dispatch trusted DOM events.
+    if (!nsContentUtils::ThreadsafeIsCallerChrome()) {
+      SetTrusted(false);
+    }
+  }
+
+  SetEventType(aEventTypeArg);
+
+  mEvent->mFlags.mBubbles = aCanBubbleArg == CanBubble::eYes;
+  mEvent->mFlags.mCancelable = aCancelableArg == Cancelable::eYes;
+  if (aComposedArg != Composed::eDefault) {
+    mEvent->mFlags.mComposed = aComposedArg == Composed::eYes;
+  }
+
+  mEvent->mFlags.mDefaultPrevented = false;
+  mEvent->mFlags.mDefaultPreventedByContent = false;
+  mEvent->mFlags.mDefaultPreventedByChrome = false;
+  mEvent->mFlags.mPropagationStopped = false;
+  mEvent->mFlags.mImmediatePropagationStopped = false;
+
+  // Clearing the old targets, so that the event is targeted correctly when
+  // re-dispatching it.
+  mEvent->mTarget = nullptr;
+  mEvent->mOriginalTarget = nullptr;
+}
+
+void Event::DuplicatePrivateData() {
+  NS_ASSERTION(mEvent, "No WidgetEvent for Event duplication!");
+  if (mEventIsInternal) {
+    return;
+  }
+
+  mEvent = mEvent->Duplicate();
+  mPresContext = nullptr;
+  mEventIsInternal = true;
+  mPrivateDataDuplicated = true;
+}
+
+void Event::SetTarget(EventTarget* aTarget) { mEvent->mTarget = aTarget; }
+
+bool Event::IsDispatchStopped() { return mEvent->PropagationStopped(); }
+
+WidgetEvent* Event::WidgetEventPtr() { return mEvent; }
+
+// static
+Maybe<CSSIntPoint> Event::GetScreenCoords(nsPresContext* aPresContext,
+                                          WidgetEvent* aEvent,
+                                          LayoutDeviceIntPoint aPoint) {
+  if (PointerLockManager::IsLocked()) {
+    return Some(EventStateManager::sLastScreenPoint);
+  }
+
+  if (!aEvent || (aEvent->mClass != eMouseEventClass &&
+                  aEvent->mClass != eMouseScrollEventClass &&
+                  aEvent->mClass != eWheelEventClass &&
+                  aEvent->mClass != ePointerEventClass &&
+                  aEvent->mClass != eTouchEventClass &&
+                  aEvent->mClass != eDragEventClass &&
+                  aEvent->mClass != eSimpleGestureEventClass)) {
+    return Nothing();
+  }
+
+  // Doing a straight conversion from LayoutDeviceIntPoint to CSSIntPoint
+  // seem incorrect, but it is needed to maintain legacy functionality.
+  WidgetGUIEvent* guiEvent = aEvent->AsGUIEvent();
+  if (!aPresContext || !(guiEvent && guiEvent->mWidget)) {
+    return Some(CSSIntPoint(aPoint.x, aPoint.y));
+  }
+
+  // (Potentially) transform the point from the coordinate space of an
+  // out-of-process iframe to the coordinate space of the native
+  // window. The transform can only be applied to a point whose components
+  // are floating-point values, so convert the integer point first, then
+  // transform, and then round the result back to an integer point.
+  LayoutDevicePoint floatPoint(aPoint);
+  LayoutDevicePoint topLevelPoint =
+      guiEvent->mWidget->WidgetToTopLevelWidgetTransform().TransformPoint(
+          floatPoint);
+  LayoutDeviceIntPoint rounded = RoundedToInt(topLevelPoint);
+
+  nsPoint pt = LayoutDevicePixel::ToAppUnits(
+      rounded, aPresContext->DeviceContext()->AppUnitsPerDevPixel());
+
+  pt += LayoutDevicePixel::ToAppUnits(
+      guiEvent->mWidget->TopLevelWidgetToScreenOffset(),
+      aPresContext->DeviceContext()->AppUnitsPerDevPixel());
+
+  return Some(CSSPixel::FromAppUnitsRounded(pt));
+}
+
+// static
+CSSIntPoint Event::GetPageCoords(nsPresContext* aPresContext,
+                                 WidgetEvent* aEvent,
+                                 LayoutDeviceIntPoint aPoint,
+                                 CSSIntPoint aDefaultPoint) {
+  CSSIntPoint pagePoint =
+      Event::GetClientCoords(aPresContext, aEvent, aPoint, aDefaultPoint);
+
+  // If there is some scrolling, add scroll info to client point.
+  if (aPresContext && aPresContext->GetPresShell()) {
+    PresShell* presShell = aPresContext->PresShell();
+    nsIScrollableFrame* scrollframe =
+        presShell->GetRootScrollFrameAsScrollable();
+    if (scrollframe) {
+      pagePoint +=
+          CSSIntPoint::FromAppUnitsRounded(scrollframe->GetScrollPosition());
+    }
+  }
+
+  return pagePoint;
+}
+
+// static
+CSSIntPoint Event::GetClientCoords(nsPresContext* aPresContext,
+                                   WidgetEvent* aEvent,
+                                   LayoutDeviceIntPoint aPoint,
+                                   CSSIntPoint aDefaultPoint) {
+  if (PointerLockManager::IsLocked()) {
+    return EventStateManager::sLastClientPoint;
+  }
+
+  if (!aEvent ||
+      (aEvent->mClass != eMouseEventClass &&
+       aEvent->mClass != eMouseScrollEventClass &&
+       aEvent->mClass != eWheelEventClass &&
+       aEvent->mClass != eTouchEventClass &&
+       aEvent->mClass != eDragEventClass &&
+       aEvent->mClass != ePointerEventClass &&
+       aEvent->mClass != eSimpleGestureEventClass) ||
+      !aPresContext || !aEvent->AsGUIEvent()->mWidget) {
+    return aDefaultPoint;
+  }
+
+  PresShell* presShell = aPresContext->GetPresShell();
+  if (!presShell) {
+    return CSSIntPoint(0, 0);
+  }
+  nsIFrame* rootFrame = presShell->GetRootFrame();
+  if (!rootFrame) {
+    return CSSIntPoint(0, 0);
+  }
+  nsPoint pt = nsLayoutUtils::GetEventCoordinatesRelativeTo(
+      aEvent, aPoint, RelativeTo{rootFrame});
+
+  return CSSIntPoint::FromAppUnitsRounded(pt);
+}
+
+// static
+CSSIntPoint Event::GetOffsetCoords(nsPresContext* aPresContext,
+                                   WidgetEvent* aEvent,
+                                   LayoutDeviceIntPoint aPoint,
+                                   CSSIntPoint aDefaultPoint) {
+  if (!aEvent->mTarget) {
+    return GetPageCoords(aPresContext, aEvent, aPoint, aDefaultPoint);
+  }
+  nsCOMPtr<nsIContent> content = nsIContent::FromEventTarget(aEvent->mTarget);
+  if (!content || !aPresContext) {
+    return CSSIntPoint();
+  }
+  RefPtr<PresShell> presShell = aPresContext->GetPresShell();
+  if (!presShell) {
+    return CSSIntPoint();
+  }
+  presShell->FlushPendingNotifications(FlushType::Layout);
+  nsIFrame* frame = content->GetPrimaryFrame();
+  if (!frame) {
+    return CSSIntPoint();
+  }
+  // For compat, see https://github.com/w3c/csswg-drafts/issues/1508. In SVG we
+  // just return the coordinates of the outer SVG box. This is all kinda
+  // unfortunate.
+  if (frame->HasAnyStateBits(NS_FRAME_SVG_LAYOUT) &&
+      StaticPrefs::dom_events_offset_in_svg_relative_to_svg_root()) {
+    frame = SVGUtils::GetOuterSVGFrame(frame);
+    if (!frame) {
+      return CSSIntPoint();
+    }
+  }
+  nsIFrame* rootFrame = presShell->GetRootFrame();
+  if (!rootFrame) {
+    return CSSIntPoint();
+  }
+  CSSIntPoint clientCoords =
+      GetClientCoords(aPresContext, aEvent, aPoint, aDefaultPoint);
+  nsPoint pt = CSSPixel::ToAppUnits(clientCoords);
+  if (nsLayoutUtils::TransformPoint(RelativeTo{rootFrame}, RelativeTo{frame},
+                                    pt) == nsLayoutUtils::TRANSFORM_SUCCEEDED) {
+    pt -= frame->GetPaddingRectRelativeToSelf().TopLeft();
+    return CSSPixel::FromAppUnitsRounded(pt);
+  }
+  return CSSIntPoint();
+}
+
+// To be called ONLY by Event::GetType (which has the additional
+// logic for handling user-defined events).
+// static
+const char16_t* Event::GetEventName(EventMessage aEventType) {
+  switch (aEventType) {
+#define MESSAGE_TO_EVENT(name_, _message, _type, _struct) \
+  case _message:                                          \
+    return u"" #name_;
+#include "mozilla/EventNameList.h"
+#undef MESSAGE_TO_EVENT
+    default:
+      break;
+  }
+  // XXXldb We can hit this case for WidgetEvent objects that we didn't
+  // create and that are not user defined events since this function and
+  // SetEventType are incomplete.  (But fixing that requires fixing the
+  // arrays in nsEventListenerManager too, since the events for which
+  // this is a problem generally *are* created by Event.)
+  return nullptr;
+}
+
+bool Event::DefaultPrevented(CallerType aCallerType) const {
+  NS_ENSURE_TRUE(mEvent, false);
+
+  // If preventDefault() has never been called, just return false.
+  if (!mEvent->DefaultPrevented()) {
+    return false;
+  }
+
+  // If preventDefault() has been called by content, return true.  Otherwise,
+  // i.e., preventDefault() has been called by chrome, return true only when
+  // this is called by chrome.
+  return mEvent->DefaultPreventedByContent() ||
+         aCallerType == CallerType::System;
+}
+
+bool Event::ReturnValue(CallerType aCallerType) const {
+  return !DefaultPrevented(aCallerType);
+}
+
+void Event::SetReturnValue(bool aReturnValue, CallerType aCallerType) {
+  if (!aReturnValue) {
+    PreventDefaultInternal(aCallerType == CallerType::System);
+  }
+}
+
+double Event::TimeStamp() {
+  if (mEvent->mTimeStamp.IsNull()) {
+    return 0.0;
+  }
+
+  if (mIsMainThreadEvent) {
+    if (NS_WARN_IF(!mOwner)) {
+      return 0.0;
+    }
+
+    nsCOMPtr<nsPIDOMWindowInner> win = do_QueryInterface(mOwner);
+    if (NS_WARN_IF(!win)) {
+      return 0.0;
+    }
+
+    Performance* perf = win->GetPerformance();
+    if (NS_WARN_IF(!perf)) {
+      return 0.0;
+    }
+
+    double ret =
+        perf->GetDOMTiming()->TimeStampToDOMHighRes(mEvent->mTimeStamp);
+    MOZ_ASSERT(mOwner->PrincipalOrNull());
+
+    return nsRFPService::ReduceTimePrecisionAsMSecs(
+        ret, perf->GetRandomTimelineSeed(), perf->GetRTPCallerType());
+  }
+
+  WorkerPrivate* workerPrivate = GetCurrentThreadWorkerPrivate();
+  MOZ_ASSERT(workerPrivate);
+
+  double ret = workerPrivate->TimeStampToDOMHighRes(mEvent->mTimeStamp);
+
+  return nsRFPService::ReduceTimePrecisionAsMSecs(
+      ret, workerPrivate->GetRandomTimelineSeed(),
+      workerPrivate->GlobalScope()->GetRTPCallerType());
+}
+
+void Event::Serialize(IPC::MessageWriter* aWriter,
+                      bool aSerializeInterfaceType) {
+  if (aSerializeInterfaceType) {
+    IPC::WriteParam(aWriter, u"event"_ns);
+  }
+
+  nsString type;
+  GetType(type);
+  IPC::WriteParam(aWriter, type);
+
+  IPC::WriteParam(aWriter, Bubbles());
+  IPC::WriteParam(aWriter, Cancelable());
+  IPC::WriteParam(aWriter, IsTrusted());
+  IPC::WriteParam(aWriter, Composed());
+
+  // No timestamp serialization for now!
+}
+
+bool Event::Deserialize(IPC::MessageReader* aReader) {
+  nsString type;
+  NS_ENSURE_TRUE(IPC::ReadParam(aReader, &type), false);
+
+  bool bubbles = false;
+  NS_ENSURE_TRUE(IPC::ReadParam(aReader, &bubbles), false);
+
+  bool cancelable = false;
+  NS_ENSURE_TRUE(IPC::ReadParam(aReader, &cancelable), false);
+
+  bool trusted = false;
+  NS_ENSURE_TRUE(IPC::ReadParam(aReader, &trusted), false);
+
+  bool composed = false;
+  NS_ENSURE_TRUE(IPC::ReadParam(aReader, &composed), false);
+
+  InitEvent(type, bubbles, cancelable);
+  SetTrusted(trusted);
+  SetComposed(composed);
+
+  return true;
+}
+
+void Event::SetOwner(EventTarget* aOwner) {
+  mOwner = nullptr;
+
+  if (!aOwner) {
+    return;
+  }
+
+  nsCOMPtr<nsINode> n = do_QueryInterface(aOwner);
+  if (n) {
+    mOwner = n->OwnerDoc()->GetScopeObject();
+    return;
+  }
+
+  nsCOMPtr<nsPIDOMWindowInner> w = do_QueryInterface(aOwner);
+  if (w) {
+    mOwner = do_QueryInterface(w);
+    return;
+  }
+
+  nsCOMPtr<DOMEventTargetHelper> eth = do_QueryInterface(aOwner);
+  if (eth) {
+    mOwner = eth->GetParentObject();
+    return;
+  }
+
+#ifdef DEBUG
+  nsCOMPtr<nsPIWindowRoot> root = do_QueryInterface(aOwner);
+  MOZ_ASSERT(root, "Unexpected EventTarget!");
+#endif
+}
+
+void Event::GetWidgetEventType(WidgetEvent* aEvent, nsAString& aType) {
+  if (!aEvent->mSpecifiedEventTypeString.IsEmpty()) {
+    aType = aEvent->mSpecifiedEventTypeString;
+    return;
+  }
+
+  const char16_t* name = GetEventName(aEvent->mMessage);
+
+  if (name) {
+    aType.Assign(name);
+    return;
+  } else if (aEvent->mMessage == eUnidentifiedEvent &&
+             aEvent->mSpecifiedEventType) {
+    // Remove "on"
+    aType = Substring(nsDependentAtomString(aEvent->mSpecifiedEventType), 2);
+    aEvent->mSpecifiedEventTypeString = aType;
+    return;
+  }
+
+  aType.Truncate();
+}
+
+bool Event::IsDragExitEnabled(JSContext* aCx, JSObject* aGlobal) {
+  return StaticPrefs::dom_event_dragexit_enabled() ||
+         nsContentUtils::IsSystemCaller(aCx);
+}
+
+}  // namespace mozilla::dom
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+already_AddRefed<Event> NS_NewDOMEvent(EventTarget* aOwner,
+                                       nsPresContext* aPresContext,
+                                       WidgetEvent* aEvent) {
+  RefPtr<Event> it = new Event(aOwner, aPresContext, aEvent);
+  return it.forget();
+}