Adding upstream version 86.0.1.upstream/86.0.1upstream

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

1 files changed, 1390 insertions, 0 deletions

diff --git a/widget/TextEvents.h b/widget/TextEvents.h
new file mode 100644
index 0000000000..f4cffc1f6f
--- /dev/null
+++ b/widget/TextEvents.h
@@ -0,0 +1,1390 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/. */
+
+#ifndef mozilla_TextEvents_h__
+#define mozilla_TextEvents_h__
+
+#include <stdint.h>
+
+#include "mozilla/Assertions.h"
+#include "mozilla/BasicEvents.h"
+#include "mozilla/CheckedInt.h"
+#include "mozilla/EventForwards.h"  // for KeyNameIndex, temporarily
+#include "mozilla/FontRange.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/OwningNonNull.h"
+#include "mozilla/TextRange.h"
+#include "mozilla/WritingModes.h"
+#include "mozilla/dom/DataTransfer.h"
+#include "mozilla/dom/KeyboardEventBinding.h"
+#include "mozilla/dom/StaticRange.h"
+#include "mozilla/widget/IMEData.h"
+#include "nsCOMPtr.h"
+#include "nsISelectionListener.h"
+#include "nsITransferable.h"
+#include "nsRect.h"
+#include "nsString.h"
+#include "nsTArray.h"
+
+class nsStringHashKey;
+template <class, class>
+class nsDataHashtable;
+
+/******************************************************************************
+ * virtual keycode values
+ ******************************************************************************/
+
+enum {
+#define NS_DEFINE_VK(aDOMKeyName, aDOMKeyCode) NS_##aDOMKeyName = aDOMKeyCode,
+#include "mozilla/VirtualKeyCodeList.h"
+#undef NS_DEFINE_VK
+  NS_VK_UNKNOWN = 0xFF
+};
+
+namespace mozilla {
+
+enum : uint32_t {
+  eKeyLocationStandard = dom::KeyboardEvent_Binding::DOM_KEY_LOCATION_STANDARD,
+  eKeyLocationLeft = dom::KeyboardEvent_Binding::DOM_KEY_LOCATION_LEFT,
+  eKeyLocationRight = dom::KeyboardEvent_Binding::DOM_KEY_LOCATION_RIGHT,
+  eKeyLocationNumpad = dom::KeyboardEvent_Binding::DOM_KEY_LOCATION_NUMPAD
+};
+
+const nsCString GetDOMKeyCodeName(uint32_t aKeyCode);
+
+namespace dom {
+class PBrowserParent;
+class PBrowserChild;
+}  // namespace dom
+namespace plugins {
+class PPluginInstanceChild;
+}  // namespace plugins
+
+enum class AccessKeyType {
+  // Handle access key for chrome.
+  eChrome,
+  // Handle access key for content.
+  eContent,
+  // Don't handle access key.
+  eNone
+};
+
+/******************************************************************************
+ * mozilla::AlternativeCharCode
+ *
+ * This stores alternative charCode values of a key event with some modifiers.
+ * The stored values proper for testing shortcut key or access key.
+ ******************************************************************************/
+
+struct AlternativeCharCode {
+  AlternativeCharCode() : mUnshiftedCharCode(0), mShiftedCharCode(0) {}
+  AlternativeCharCode(uint32_t aUnshiftedCharCode, uint32_t aShiftedCharCode)
+      : mUnshiftedCharCode(aUnshiftedCharCode),
+        mShiftedCharCode(aShiftedCharCode) {}
+  uint32_t mUnshiftedCharCode;
+  uint32_t mShiftedCharCode;
+};
+
+/******************************************************************************
+ * mozilla::ShortcutKeyCandidate
+ *
+ * This stores a candidate of shortcut key combination.
+ ******************************************************************************/
+
+struct ShortcutKeyCandidate {
+  ShortcutKeyCandidate() : mCharCode(0), mIgnoreShift(0) {}
+  ShortcutKeyCandidate(uint32_t aCharCode, bool aIgnoreShift)
+      : mCharCode(aCharCode), mIgnoreShift(aIgnoreShift) {}
+  // The mCharCode value which must match keyboard shortcut definition.
+  uint32_t mCharCode;
+  // true if Shift state can be ignored.  Otherwise, Shift key state must
+  // match keyboard shortcut definition.
+  bool mIgnoreShift;
+};
+
+/******************************************************************************
+ * mozilla::IgnoreModifierState
+ *
+ * This stores flags for modifiers that should be ignored when matching
+ * XBL handlers.
+ ******************************************************************************/
+
+struct IgnoreModifierState {
+  // When mShift is true, Shift key state will be ignored.
+  bool mShift;
+  // When mOS is true, OS key state will be ignored.
+  bool mOS;
+
+  IgnoreModifierState() : mShift(false), mOS(false) {}
+};
+
+/******************************************************************************
+ * mozilla::WidgetKeyboardEvent
+ ******************************************************************************/
+
+class WidgetKeyboardEvent : public WidgetInputEvent {
+ private:
+  friend class dom::PBrowserParent;
+  friend class dom::PBrowserChild;
+  friend struct IPC::ParamTraits<WidgetKeyboardEvent>;
+
+ protected:
+  WidgetKeyboardEvent()
+      : mNativeKeyEvent(nullptr),
+        mKeyCode(0),
+        mCharCode(0),
+        mPseudoCharCode(0),
+        mLocation(eKeyLocationStandard),
+        mUniqueId(0),
+        mKeyNameIndex(KEY_NAME_INDEX_Unidentified),
+        mCodeNameIndex(CODE_NAME_INDEX_UNKNOWN),
+        mIsRepeat(false),
+        mIsComposing(false),
+        mIsSynthesizedByTIP(false),
+        mMaybeSkippableInRemoteProcess(true),
+        mUseLegacyKeyCodeAndCharCodeValues(false),
+        mEditCommandsForSingleLineEditorInitialized(false),
+        mEditCommandsForMultiLineEditorInitialized(false),
+        mEditCommandsForRichTextEditorInitialized(false) {}
+
+ public:
+  virtual WidgetKeyboardEvent* AsKeyboardEvent() override { return this; }
+
+  WidgetKeyboardEvent(bool aIsTrusted, EventMessage aMessage,
+                      nsIWidget* aWidget,
+                      EventClassID aEventClassID = eKeyboardEventClass)
+      : WidgetInputEvent(aIsTrusted, aMessage, aWidget, aEventClassID),
+        mNativeKeyEvent(nullptr),
+        mKeyCode(0),
+        mCharCode(0),
+        mPseudoCharCode(0),
+        mLocation(eKeyLocationStandard),
+        mUniqueId(0),
+        mKeyNameIndex(KEY_NAME_INDEX_Unidentified),
+        mCodeNameIndex(CODE_NAME_INDEX_UNKNOWN),
+        mIsRepeat(false),
+        mIsComposing(false),
+        mIsSynthesizedByTIP(false),
+        mMaybeSkippableInRemoteProcess(true),
+        mUseLegacyKeyCodeAndCharCodeValues(false),
+        mEditCommandsForSingleLineEditorInitialized(false),
+        mEditCommandsForMultiLineEditorInitialized(false),
+        mEditCommandsForRichTextEditorInitialized(false) {
+    // If this is a keyboard event on a plugin, it shouldn't fired on content.
+    if (IsKeyEventOnPlugin()) {
+      mFlags.mOnlySystemGroupDispatchInContent = true;
+      StopCrossProcessForwarding();
+    }
+  }
+
+  static bool IsKeyDownOrKeyDownOnPlugin(EventMessage aMessage) {
+    return aMessage == eKeyDown || aMessage == eKeyDownOnPlugin;
+  }
+  bool IsKeyDownOrKeyDownOnPlugin() const {
+    return IsKeyDownOrKeyDownOnPlugin(mMessage);
+  }
+  static bool IsKeyUpOrKeyUpOnPlugin(EventMessage aMessage) {
+    return aMessage == eKeyUp || aMessage == eKeyUpOnPlugin;
+  }
+  bool IsKeyUpOrKeyUpOnPlugin() const {
+    return IsKeyUpOrKeyUpOnPlugin(mMessage);
+  }
+  static bool IsKeyEventOnPlugin(EventMessage aMessage) {
+    return aMessage == eKeyDownOnPlugin || aMessage == eKeyUpOnPlugin;
+  }
+  bool IsKeyEventOnPlugin() const { return IsKeyEventOnPlugin(mMessage); }
+
+  // IsInputtingText() and IsInputtingLineBreak() are used to check if
+  // it should cause eKeyPress events even on web content.
+  // UI Events defines that "keypress" event should be fired "if and only if
+  // that key normally produces a character value".
+  // <https://www.w3.org/TR/uievents/#event-type-keypress>
+  // Additionally, for backward compatiblity with all existing browsers,
+  // there is a spec issue for Enter key press.
+  // <https://github.com/w3c/uievents/issues/183>
+  bool IsInputtingText() const {
+    // NOTE: On some keyboard layout, some characters are inputted with Control
+    //       key or Alt key, but at that time, widget clears the modifier flag
+    //       from eKeyPress event because our TextEditor won't handle eKeyPress
+    //       events as inputting text (bug 1346832).
+    // NOTE: There are some complicated issues of our traditional behavior.
+    //       -- On Windows, KeyboardLayout::WillDispatchKeyboardEvent() clears
+    //       MODIFIER_ALT and MODIFIER_CONTROL of eKeyPress event if it
+    //       should be treated as inputting a character because AltGr is
+    //       represented with both Alt key and Ctrl key are pressed, and
+    //       some keyboard layouts may produces a character with Ctrl key.
+    //       -- On Linux, KeymapWrapper doesn't have this hack since perhaps,
+    //       we don't have any bug reports that user cannot input proper
+    //       character with Alt and/or Ctrl key.
+    //       -- On macOS, IMEInputHandler::WillDispatchKeyboardEvent() clears
+    //       MODIFIER_ALT and MDOFIEIR_CONTROL of eKeyPress event only when
+    //       TextInputHandler::InsertText() has been called for the event.
+    //       I.e., they are cleared only when an editor has focus (even if IME
+    //       is disabled in password field or by |ime-mode: disabled;|) because
+    //       TextInputHandler::InsertText() is called while
+    //       TextInputHandler::HandleKeyDownEvent() calls interpretKeyEvents:
+    //       to notify text input processor of Cocoa (including IME).  In other
+    //       words, when we need to disable IME completey when no editor has
+    //       focus, we cannot call interpretKeyEvents:.  So,
+    //       TextInputHandler::InsertText() won't be called when no editor has
+    //       focus so that neither MODIFIER_ALT nor MODIFIER_CONTROL is
+    //       cleared.  So, fortunately, altKey and ctrlKey values of "keypress"
+    //       events are same as the other browsers only when no editor has
+    //       focus.
+    // NOTE: As mentioned above, for compatibility with the other browsers on
+    //       macOS, we should keep MODIFIER_ALT and MODIFIER_CONTROL flags of
+    //       eKeyPress events when no editor has focus.  However, Alt key,
+    //       labeled "option" on keyboard for Mac, is AltGraph key on the other
+    //       platforms.  So, even if MODIFIER_ALT is set, we need to dispatch
+    //       eKeyPress event even on web content unless mCharCode is 0.
+    //       Therefore, we need to ignore MODIFIER_ALT flag here only on macOS.
+    return mMessage == eKeyPress && mCharCode &&
+           !(mModifiers & (
+#ifndef XP_MACOSX
+                              // So, ignore MODIFIER_ALT only on macOS since
+                              // option key is used as AltGraph key on macOS.
+                              MODIFIER_ALT |
+#endif  // #ifndef XP_MAXOSX
+                              MODIFIER_CONTROL | MODIFIER_META | MODIFIER_OS));
+  }
+
+  bool IsInputtingLineBreak() const {
+    return mMessage == eKeyPress && mKeyNameIndex == KEY_NAME_INDEX_Enter &&
+           !(mModifiers &
+             (MODIFIER_ALT | MODIFIER_CONTROL | MODIFIER_META | MODIFIER_OS));
+  }
+
+  /**
+   * ShouldKeyPressEventBeFiredOnContent() should be called only when the
+   * instance is eKeyPress event.  This returns true when the eKeyPress
+   * event should be fired even on content in the default event group.
+   */
+  bool ShouldKeyPressEventBeFiredOnContent() const {
+    MOZ_DIAGNOSTIC_ASSERT(mMessage == eKeyPress);
+    if (IsInputtingText() || IsInputtingLineBreak()) {
+      return true;
+    }
+    // Ctrl + Enter won't cause actual input in our editor.
+    // However, the other browsers fire keypress event in any platforms.
+    // So, for compatibility with them, we should fire keypress event for
+    // Ctrl + Enter too.
+    return mMessage == eKeyPress && mKeyNameIndex == KEY_NAME_INDEX_Enter &&
+           !(mModifiers &
+             (MODIFIER_ALT | MODIFIER_META | MODIFIER_OS | MODIFIER_SHIFT));
+  }
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eKeyboardEventClass,
+               "Duplicate() must be overridden by sub class");
+    // Not copying widget, it is a weak reference.
+    WidgetKeyboardEvent* result =
+        new WidgetKeyboardEvent(false, mMessage, nullptr);
+    result->AssignKeyEventData(*this, true);
+    result->mEditCommandsForSingleLineEditor =
+        mEditCommandsForSingleLineEditor.Clone();
+    result->mEditCommandsForMultiLineEditor =
+        mEditCommandsForMultiLineEditor.Clone();
+    result->mEditCommandsForRichTextEditor =
+        mEditCommandsForRichTextEditor.Clone();
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  bool CanUserGestureActivateTarget() const {
+    // Printable keys, 'carriage return' and 'space' are supported user gestures
+    // for activating the document. However, if supported key is being pressed
+    // combining with other operation keys, such like alt, control ..etc., we
+    // won't activate the target for them because at that time user might
+    // interact with browser or window manager which doesn't necessarily
+    // demonstrate user's intent to play media.
+    const bool isCombiningWithOperationKeys = (IsControl() && !IsAltGraph()) ||
+                                              (IsAlt() && !IsAltGraph()) ||
+                                              IsMeta() || IsOS();
+    const bool isEnterOrSpaceKey =
+        mKeyNameIndex == KEY_NAME_INDEX_Enter || mKeyCode == NS_VK_SPACE;
+    return (PseudoCharCode() || isEnterOrSpaceKey) &&
+           (!isCombiningWithOperationKeys ||
+            // ctrl-c/ctrl-x/ctrl-v is quite common shortcut for clipboard
+            // operation.
+            // XXXedgar, we have to find a better way to handle browser keyboard
+            // shortcut for user activation, instead of just ignoring all
+            // combinations, see bug 1641171.
+            ((mKeyCode == dom::KeyboardEvent_Binding::DOM_VK_C ||
+              mKeyCode == dom::KeyboardEvent_Binding::DOM_VK_V ||
+              mKeyCode == dom::KeyboardEvent_Binding::DOM_VK_X) &&
+             IsAccel()));
+  }
+
+  /**
+   * CanTreatAsUserInput() returns true if the key is pressed for perhaps
+   * doing something on the web app or our UI.  This means that when this
+   * returns false, e.g., when user presses a modifier key, user is probably
+   * displeased by opening popup, entering fullscreen mode, etc.  Therefore,
+   * only when this returns true, such reactions should be allowed.
+   */
+  bool CanTreatAsUserInput() const {
+    if (!IsTrusted()) {
+      return false;
+    }
+    switch (mKeyNameIndex) {
+      case KEY_NAME_INDEX_Escape:
+      // modifier keys:
+      case KEY_NAME_INDEX_Alt:
+      case KEY_NAME_INDEX_AltGraph:
+      case KEY_NAME_INDEX_CapsLock:
+      case KEY_NAME_INDEX_Control:
+      case KEY_NAME_INDEX_Fn:
+      case KEY_NAME_INDEX_FnLock:
+      case KEY_NAME_INDEX_Meta:
+      case KEY_NAME_INDEX_NumLock:
+      case KEY_NAME_INDEX_ScrollLock:
+      case KEY_NAME_INDEX_Shift:
+      case KEY_NAME_INDEX_Symbol:
+      case KEY_NAME_INDEX_SymbolLock:
+      // legacy modifier keys:
+      case KEY_NAME_INDEX_Hyper:
+      case KEY_NAME_INDEX_Super:
+      // obsolete modifier key:
+      case KEY_NAME_INDEX_OS:
+        return false;
+      default:
+        return true;
+    }
+  }
+
+  /**
+   * ShouldInteractionTimeRecorded() returns true if the handling time of
+   * the event should be recorded with the telemetry.
+   */
+  bool ShouldInteractionTimeRecorded() const {
+    // Let's record only when we can treat the instance is a user input.
+    return CanTreatAsUserInput();
+  }
+
+  // OS translated Unicode chars which are used for accesskey and accelkey
+  // handling. The handlers will try from first character to last character.
+  CopyableTArray<AlternativeCharCode> mAlternativeCharCodes;
+  // DOM KeyboardEvent.key only when mKeyNameIndex is KEY_NAME_INDEX_USE_STRING.
+  nsString mKeyValue;
+  // DOM KeyboardEvent.code only when mCodeNameIndex is
+  // CODE_NAME_INDEX_USE_STRING.
+  nsString mCodeValue;
+
+  // OS-specific native event can optionally be preserved.
+  // This is used to retrieve editing shortcut keys in the environment.
+  void* mNativeKeyEvent;
+  // A DOM keyCode value or 0.  If a keypress event whose mCharCode is 0, this
+  // should be 0.
+  uint32_t mKeyCode;
+  // If the instance is a keypress event of a printable key, this is a UTF-16
+  // value of the key.  Otherwise, 0.  This value must not be a control
+  // character when some modifiers are active.  Then, this value should be an
+  // unmodified value except Shift and AltGr.
+  uint32_t mCharCode;
+  // mPseudoCharCode is valid only when mMessage is an eKeyDown event.
+  // This stores mCharCode value of keypress event which is fired with same
+  // key value and same modifier state.
+  uint32_t mPseudoCharCode;
+  // One of eKeyLocation*
+  uint32_t mLocation;
+  // Unique id associated with a keydown / keypress event. It's ok if this wraps
+  // over long periods.
+  uint32_t mUniqueId;
+
+  // DOM KeyboardEvent.key
+  KeyNameIndex mKeyNameIndex;
+  // DOM KeyboardEvent.code
+  CodeNameIndex mCodeNameIndex;
+
+  // Indicates whether the event is generated by auto repeat or not.
+  // if this is keyup event, always false.
+  bool mIsRepeat;
+  // Indicates whether the event is generated during IME (or deadkey)
+  // composition.  This is initialized by EventStateManager.  So, key event
+  // dispatchers don't need to initialize this.
+  bool mIsComposing;
+  // Indicates whether the event is synthesized from Text Input Processor
+  // or an actual event from nsAppShell.
+  bool mIsSynthesizedByTIP;
+  // Indicates whether the event is skippable in remote process.
+  // Don't refer this member directly when you need to check this.
+  // Use CanSkipInRemoteProcess() instead.
+  bool mMaybeSkippableInRemoteProcess;
+  // Indicates whether the event should return legacy keyCode value and
+  // charCode value to web apps (one of them is always 0) or not, when it's
+  // an eKeyPress event.
+  bool mUseLegacyKeyCodeAndCharCodeValues;
+
+  bool CanSkipInRemoteProcess() const {
+    // If this is a repeat event (i.e., generated by auto-repeat feature of
+    // the platform), remove process may skip to handle it because of
+    // performances reasons..  However, if it's caused by odd keyboard utils,
+    // we should not ignore any key events even marked as repeated since
+    // generated key sequence may be important to input proper text.  E.g.,
+    // "SinhalaTamil IME" on Windows emulates dead key like input with
+    // generating WM_KEYDOWN for VK_PACKET (inputting any Unicode characters
+    // without keyboard layout information) and VK_BACK (Backspace) to remove
+    // previous character(s) and those messages may be marked as "repeat" by
+    // their bug.
+    return mIsRepeat && mMaybeSkippableInRemoteProcess;
+  }
+
+  /**
+   * Retrieves all edit commands from mWidget.  This shouldn't be called when
+   * the instance is an untrusted event, doesn't have widget or in non-chrome
+   * process.
+   */
+  void InitAllEditCommands();
+
+  /**
+   * Retrieves edit commands from mWidget only for aType.  This shouldn't be
+   * called when the instance is an untrusted event or doesn't have widget.
+   *
+   * @return            false if some resource is not available to get
+   *                    commands unexpectedly.  Otherwise, true even if
+   *                    retrieved command is nothing.
+   */
+  bool InitEditCommandsFor(nsIWidget::NativeKeyBindingsType aType);
+
+  /**
+   * PreventNativeKeyBindings() makes the instance to not cause any edit
+   * actions even if it matches with a native key binding.
+   */
+  void PreventNativeKeyBindings() {
+    mEditCommandsForSingleLineEditor.Clear();
+    mEditCommandsForMultiLineEditor.Clear();
+    mEditCommandsForRichTextEditor.Clear();
+    mEditCommandsForSingleLineEditorInitialized = true;
+    mEditCommandsForMultiLineEditorInitialized = true;
+    mEditCommandsForRichTextEditorInitialized = true;
+  }
+
+  /**
+   * EditCommandsConstRef() returns reference to edit commands for aType.
+   */
+  const nsTArray<CommandInt>& EditCommandsConstRef(
+      nsIWidget::NativeKeyBindingsType aType) const {
+    return const_cast<WidgetKeyboardEvent*>(this)->EditCommandsRef(aType);
+  }
+
+  /**
+   * IsEditCommandsInitialized() returns true if edit commands for aType
+   * was already initialized.  Otherwise, false.
+   */
+  bool IsEditCommandsInitialized(nsIWidget::NativeKeyBindingsType aType) const {
+    return const_cast<WidgetKeyboardEvent*>(this)->IsEditCommandsInitializedRef(
+        aType);
+  }
+
+#ifdef DEBUG
+  /**
+   * AreAllEditCommandsInitialized() returns true if edit commands for all
+   * types were already initialized.  Otherwise, false.
+   */
+  bool AreAllEditCommandsInitialized() const {
+    return mEditCommandsForSingleLineEditorInitialized &&
+           mEditCommandsForMultiLineEditorInitialized &&
+           mEditCommandsForRichTextEditorInitialized;
+  }
+#endif  // #ifdef DEBUG
+
+  /**
+   * Execute edit commands for aType.
+   *
+   * @return        true if the caller should do nothing anymore.
+   *                false, otherwise.
+   */
+  typedef void (*DoCommandCallback)(Command, void*);
+  bool ExecuteEditCommands(nsIWidget::NativeKeyBindingsType aType,
+                           DoCommandCallback aCallback, void* aCallbackData);
+
+  // If the key should cause keypress events, this returns true.
+  // Otherwise, false.
+  bool ShouldCauseKeypressEvents() const;
+
+  // mCharCode value of non-eKeyPress events is always 0.  However, if
+  // non-eKeyPress event has one or more alternative char code values,
+  // its first item should be the mCharCode value of following eKeyPress event.
+  // PseudoCharCode() returns mCharCode value for eKeyPress event,
+  // the first alternative char code value of non-eKeyPress event or 0.
+  uint32_t PseudoCharCode() const {
+    return mMessage == eKeyPress ? mCharCode : mPseudoCharCode;
+  }
+  void SetCharCode(uint32_t aCharCode) {
+    if (mMessage == eKeyPress) {
+      mCharCode = aCharCode;
+    } else {
+      mPseudoCharCode = aCharCode;
+    }
+  }
+
+  void GetDOMKeyName(nsAString& aKeyName) {
+    if (mKeyNameIndex == KEY_NAME_INDEX_USE_STRING) {
+      aKeyName = mKeyValue;
+      return;
+    }
+    GetDOMKeyName(mKeyNameIndex, aKeyName);
+  }
+  void GetDOMCodeName(nsAString& aCodeName) {
+    if (mCodeNameIndex == CODE_NAME_INDEX_USE_STRING) {
+      aCodeName = mCodeValue;
+      return;
+    }
+    GetDOMCodeName(mCodeNameIndex, aCodeName);
+  }
+
+  /**
+   * GetFallbackKeyCodeOfPunctuationKey() returns a DOM keyCode value for
+   * aCodeNameIndex.  This is keyCode value of the key when active keyboard
+   * layout is ANSI (US), JIS or ABNT keyboard layout (the latter 2 layouts
+   * are used only when ANSI doesn't have the key).  The result is useful
+   * if the key doesn't produce ASCII character with active keyboard layout
+   * nor with alternative ASCII capable keyboard layout.
+   */
+  static uint32_t GetFallbackKeyCodeOfPunctuationKey(
+      CodeNameIndex aCodeNameIndex);
+
+  bool IsModifierKeyEvent() const {
+    return GetModifierForKeyName(mKeyNameIndex) != MODIFIER_NONE;
+  }
+
+  /**
+   * Get the candidates for shortcut key.
+   *
+   * @param aCandidates [out] the candidate shortcut key combination list.
+   *                          the first item is most preferred.
+   */
+  void GetShortcutKeyCandidates(ShortcutKeyCandidateArray& aCandidates) const;
+
+  /**
+   * Get the candidates for access key.
+   *
+   * @param aCandidates [out] the candidate access key list.
+   *                          the first item is most preferred.
+   */
+  void GetAccessKeyCandidates(nsTArray<uint32_t>& aCandidates) const;
+
+  /**
+   * Check whether the modifiers match with chrome access key or
+   * content access key.
+   */
+  bool ModifiersMatchWithAccessKey(AccessKeyType aType) const;
+
+  /**
+   * Return active modifiers which may match with access key.
+   * For example, even if Alt is access key modifier, then, when Control,
+   * CapseLock and NumLock are active, this returns only MODIFIER_CONTROL.
+   */
+  Modifiers ModifiersForAccessKeyMatching() const;
+
+  /**
+   * Return access key modifiers.
+   */
+  static Modifiers AccessKeyModifiers(AccessKeyType aType);
+
+  static void Shutdown();
+
+  /**
+   * ComputeLocationFromCodeValue() returns one of .mLocation value
+   * (eKeyLocation*) which is the most preferred value for the specified code
+   * value.
+   */
+  static uint32_t ComputeLocationFromCodeValue(CodeNameIndex aCodeNameIndex);
+
+  /**
+   * ComputeKeyCodeFromKeyNameIndex() return a .mKeyCode value which can be
+   * mapped from the specified key value.  Note that this returns 0 if the
+   * key name index is KEY_NAME_INDEX_Unidentified or KEY_NAME_INDEX_USE_STRING.
+   * This means that this method is useful only for non-printable keys.
+   */
+  static uint32_t ComputeKeyCodeFromKeyNameIndex(KeyNameIndex aKeyNameIndex);
+
+  /**
+   * ComputeCodeNameIndexFromKeyNameIndex() returns a code name index which
+   * is typically mapped to given key name index on the platform.
+   * Note that this returns CODE_NAME_INDEX_UNKNOWN if the key name index is
+   * KEY_NAME_INDEX_Unidentified or KEY_NAME_INDEX_USE_STRING.
+   * This means that this method is useful only for non-printable keys.
+   *
+   * @param aKeyNameIndex      A non-printable key name index.
+   * @param aLocation          Should be one of location value.  This is
+   *                           important when aKeyNameIndex may exist in
+   *                           both Numpad or Standard, or in both Left or
+   *                           Right.  If this is nothing, this method
+   *                           returns Left or Standard position's code
+   *                           value.
+   */
+  static CodeNameIndex ComputeCodeNameIndexFromKeyNameIndex(
+      KeyNameIndex aKeyNameIndex, const Maybe<uint32_t>& aLocation);
+
+  /**
+   * GetModifierForKeyName() returns a value of Modifier which is activated
+   * by the aKeyNameIndex.
+   */
+  static Modifier GetModifierForKeyName(KeyNameIndex aKeyNameIndex);
+
+  /**
+   * IsLeftOrRightModiferKeyNameIndex() returns true if aKeyNameIndex is a
+   * modifier key which may be in Left and Right location.
+   */
+  static bool IsLeftOrRightModiferKeyNameIndex(KeyNameIndex aKeyNameIndex) {
+    switch (aKeyNameIndex) {
+      case KEY_NAME_INDEX_Alt:
+      case KEY_NAME_INDEX_Control:
+      case KEY_NAME_INDEX_Meta:
+      case KEY_NAME_INDEX_OS:
+      case KEY_NAME_INDEX_Shift:
+        return true;
+      default:
+        return false;
+    }
+  }
+
+  /**
+   * IsLockableModifier() returns true if aKeyNameIndex is a lockable modifier
+   * key such as CapsLock and NumLock.
+   */
+  static bool IsLockableModifier(KeyNameIndex aKeyNameIndex);
+
+  static void GetDOMKeyName(KeyNameIndex aKeyNameIndex, nsAString& aKeyName);
+  static void GetDOMCodeName(CodeNameIndex aCodeNameIndex,
+                             nsAString& aCodeName);
+
+  static KeyNameIndex GetKeyNameIndex(const nsAString& aKeyValue);
+  static CodeNameIndex GetCodeNameIndex(const nsAString& aCodeValue);
+
+  static const char* GetCommandStr(Command aCommand);
+
+  void AssignKeyEventData(const WidgetKeyboardEvent& aEvent,
+                          bool aCopyTargets) {
+    AssignInputEventData(aEvent, aCopyTargets);
+
+    mKeyCode = aEvent.mKeyCode;
+    mCharCode = aEvent.mCharCode;
+    mPseudoCharCode = aEvent.mPseudoCharCode;
+    mLocation = aEvent.mLocation;
+    mAlternativeCharCodes = aEvent.mAlternativeCharCodes.Clone();
+    mIsRepeat = aEvent.mIsRepeat;
+    mIsComposing = aEvent.mIsComposing;
+    mKeyNameIndex = aEvent.mKeyNameIndex;
+    mCodeNameIndex = aEvent.mCodeNameIndex;
+    mKeyValue = aEvent.mKeyValue;
+    mCodeValue = aEvent.mCodeValue;
+    // Don't copy mNativeKeyEvent because it may be referred after its instance
+    // is destroyed.
+    mNativeKeyEvent = nullptr;
+    mUniqueId = aEvent.mUniqueId;
+    mIsSynthesizedByTIP = aEvent.mIsSynthesizedByTIP;
+    mMaybeSkippableInRemoteProcess = aEvent.mMaybeSkippableInRemoteProcess;
+    mUseLegacyKeyCodeAndCharCodeValues =
+        aEvent.mUseLegacyKeyCodeAndCharCodeValues;
+
+    // Don't copy mEditCommandsFor*Editor because it may require a lot of
+    // memory space.  For example, if the event is dispatched but grabbed by
+    // a JS variable, they are not necessary anymore.
+
+    mEditCommandsForSingleLineEditorInitialized =
+        aEvent.mEditCommandsForSingleLineEditorInitialized;
+    mEditCommandsForMultiLineEditorInitialized =
+        aEvent.mEditCommandsForMultiLineEditorInitialized;
+    mEditCommandsForRichTextEditorInitialized =
+        aEvent.mEditCommandsForRichTextEditorInitialized;
+  }
+
+  void AssignCommands(const WidgetKeyboardEvent& aEvent) {
+    mEditCommandsForSingleLineEditorInitialized =
+        aEvent.mEditCommandsForSingleLineEditorInitialized;
+    if (mEditCommandsForSingleLineEditorInitialized) {
+      mEditCommandsForSingleLineEditor =
+          aEvent.mEditCommandsForSingleLineEditor.Clone();
+    } else {
+      mEditCommandsForSingleLineEditor.Clear();
+    }
+    mEditCommandsForMultiLineEditorInitialized =
+        aEvent.mEditCommandsForMultiLineEditorInitialized;
+    if (mEditCommandsForMultiLineEditorInitialized) {
+      mEditCommandsForMultiLineEditor =
+          aEvent.mEditCommandsForMultiLineEditor.Clone();
+    } else {
+      mEditCommandsForMultiLineEditor.Clear();
+    }
+    mEditCommandsForRichTextEditorInitialized =
+        aEvent.mEditCommandsForRichTextEditorInitialized;
+    if (mEditCommandsForRichTextEditorInitialized) {
+      mEditCommandsForRichTextEditor =
+          aEvent.mEditCommandsForRichTextEditor.Clone();
+    } else {
+      mEditCommandsForRichTextEditor.Clear();
+    }
+  }
+
+ private:
+  static const char16_t* const kKeyNames[];
+  static const char16_t* const kCodeNames[];
+  typedef nsDataHashtable<nsStringHashKey, KeyNameIndex> KeyNameIndexHashtable;
+  typedef nsDataHashtable<nsStringHashKey, CodeNameIndex>
+      CodeNameIndexHashtable;
+  static KeyNameIndexHashtable* sKeyNameIndexHashtable;
+  static CodeNameIndexHashtable* sCodeNameIndexHashtable;
+
+  // mEditCommandsFor*Editor store edit commands.  This should be initialized
+  // with InitEditCommandsFor().
+  // XXX Ideally, this should be array of Command rather than CommandInt.
+  //     However, ParamTraits isn't aware of enum array.
+  CopyableTArray<CommandInt> mEditCommandsForSingleLineEditor;
+  CopyableTArray<CommandInt> mEditCommandsForMultiLineEditor;
+  CopyableTArray<CommandInt> mEditCommandsForRichTextEditor;
+
+  nsTArray<CommandInt>& EditCommandsRef(
+      nsIWidget::NativeKeyBindingsType aType) {
+    switch (aType) {
+      case nsIWidget::NativeKeyBindingsForSingleLineEditor:
+        return mEditCommandsForSingleLineEditor;
+      case nsIWidget::NativeKeyBindingsForMultiLineEditor:
+        return mEditCommandsForMultiLineEditor;
+      case nsIWidget::NativeKeyBindingsForRichTextEditor:
+        return mEditCommandsForRichTextEditor;
+      default:
+        MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE(
+            "Invalid native key binding type");
+    }
+  }
+
+  // mEditCommandsFor*EditorInitialized are set to true when
+  // InitEditCommandsFor() initializes edit commands for the type.
+  bool mEditCommandsForSingleLineEditorInitialized;
+  bool mEditCommandsForMultiLineEditorInitialized;
+  bool mEditCommandsForRichTextEditorInitialized;
+
+  bool& IsEditCommandsInitializedRef(nsIWidget::NativeKeyBindingsType aType) {
+    switch (aType) {
+      case nsIWidget::NativeKeyBindingsForSingleLineEditor:
+        return mEditCommandsForSingleLineEditorInitialized;
+      case nsIWidget::NativeKeyBindingsForMultiLineEditor:
+        return mEditCommandsForMultiLineEditorInitialized;
+      case nsIWidget::NativeKeyBindingsForRichTextEditor:
+        return mEditCommandsForRichTextEditorInitialized;
+      default:
+        MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE(
+            "Invalid native key binding type");
+    }
+  }
+};
+
+/******************************************************************************
+ * mozilla::WidgetCompositionEvent
+ ******************************************************************************/
+
+class WidgetCompositionEvent : public WidgetGUIEvent {
+ private:
+  friend class mozilla::dom::PBrowserParent;
+  friend class mozilla::dom::PBrowserChild;
+
+  WidgetCompositionEvent() : mOriginalMessage(eVoidEvent) {}
+
+ public:
+  virtual WidgetCompositionEvent* AsCompositionEvent() override { return this; }
+
+  WidgetCompositionEvent(bool aIsTrusted, EventMessage aMessage,
+                         nsIWidget* aWidget)
+      : WidgetGUIEvent(aIsTrusted, aMessage, aWidget, eCompositionEventClass),
+        mNativeIMEContext(aWidget),
+        mOriginalMessage(eVoidEvent) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eCompositionEventClass,
+               "Duplicate() must be overridden by sub class");
+    // Not copying widget, it is a weak reference.
+    WidgetCompositionEvent* result =
+        new WidgetCompositionEvent(false, mMessage, nullptr);
+    result->AssignCompositionEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  // The composition string or the commit string.  If the instance is a
+  // compositionstart event, this is initialized with selected text by
+  // TextComposition automatically.
+  nsString mData;
+
+  RefPtr<TextRangeArray> mRanges;
+
+  // mNativeIMEContext stores the native IME context which causes the
+  // composition event.
+  widget::NativeIMEContext mNativeIMEContext;
+
+  // If the instance is a clone of another event, mOriginalMessage stores
+  // the another event's mMessage.
+  EventMessage mOriginalMessage;
+
+  void AssignCompositionEventData(const WidgetCompositionEvent& aEvent,
+                                  bool aCopyTargets) {
+    AssignGUIEventData(aEvent, aCopyTargets);
+
+    mData = aEvent.mData;
+    mOriginalMessage = aEvent.mOriginalMessage;
+    mRanges = aEvent.mRanges;
+
+    // Currently, we don't need to copy the other members because they are
+    // for internal use only (not available from JS).
+  }
+
+  bool IsComposing() const { return mRanges && mRanges->IsComposing(); }
+
+  uint32_t TargetClauseOffset() const {
+    return mRanges ? mRanges->TargetClauseOffset() : 0;
+  }
+
+  uint32_t TargetClauseLength() const {
+    uint32_t length = UINT32_MAX;
+    if (mRanges) {
+      length = mRanges->TargetClauseLength();
+    }
+    return length == UINT32_MAX ? mData.Length() : length;
+  }
+
+  uint32_t RangeCount() const { return mRanges ? mRanges->Length() : 0; }
+
+  bool CausesDOMTextEvent() const {
+    return mMessage == eCompositionChange || mMessage == eCompositionCommit ||
+           mMessage == eCompositionCommitAsIs;
+  }
+
+  bool CausesDOMCompositionEndEvent() const {
+    return mMessage == eCompositionEnd || mMessage == eCompositionCommit ||
+           mMessage == eCompositionCommitAsIs;
+  }
+
+  bool IsFollowedByCompositionEnd() const {
+    return IsFollowedByCompositionEnd(mOriginalMessage);
+  }
+
+  static bool IsFollowedByCompositionEnd(EventMessage aEventMessage) {
+    return aEventMessage == eCompositionCommit ||
+           aEventMessage == eCompositionCommitAsIs;
+  }
+};
+
+/******************************************************************************
+ * mozilla::WidgetQueryContentEvent
+ ******************************************************************************/
+
+class WidgetQueryContentEvent : public WidgetGUIEvent {
+ private:
+  friend class dom::PBrowserParent;
+  friend class dom::PBrowserChild;
+
+  WidgetQueryContentEvent()
+      : mUseNativeLineBreak(true),
+        mWithFontRanges(false),
+        mNeedsToFlushLayout(true) {
+    MOZ_CRASH("WidgetQueryContentEvent is created without proper arguments");
+  }
+
+ public:
+  virtual WidgetQueryContentEvent* AsQueryContentEvent() override {
+    return this;
+  }
+
+  WidgetQueryContentEvent(bool aIsTrusted, EventMessage aMessage,
+                          nsIWidget* aWidget)
+      : WidgetGUIEvent(aIsTrusted, aMessage, aWidget, eQueryContentEventClass),
+        mUseNativeLineBreak(true),
+        mWithFontRanges(false),
+        mNeedsToFlushLayout(true) {}
+
+  WidgetQueryContentEvent(EventMessage aMessage,
+                          const WidgetQueryContentEvent& aOtherEvent)
+      : WidgetGUIEvent(aOtherEvent.IsTrusted(), aMessage,
+                       const_cast<nsIWidget*>(aOtherEvent.mWidget.get()),
+                       eQueryContentEventClass),
+        mUseNativeLineBreak(aOtherEvent.mUseNativeLineBreak),
+        mWithFontRanges(false),
+        mNeedsToFlushLayout(aOtherEvent.mNeedsToFlushLayout) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    // This event isn't an internal event of any DOM event.
+    NS_ASSERTION(!IsAllowedToDispatchDOMEvent(),
+                 "WidgetQueryContentEvent needs to support Duplicate()");
+    MOZ_CRASH("WidgetQueryContentEvent doesn't support Duplicate()");
+  }
+
+  struct Options final {
+    bool mUseNativeLineBreak;
+    bool mRelativeToInsertionPoint;
+
+    explicit Options()
+        : mUseNativeLineBreak(true), mRelativeToInsertionPoint(false) {}
+
+    explicit Options(const WidgetQueryContentEvent& aEvent)
+        : mUseNativeLineBreak(aEvent.mUseNativeLineBreak),
+          mRelativeToInsertionPoint(aEvent.mInput.mRelativeToInsertionPoint) {}
+  };
+
+  void Init(const Options& aOptions) {
+    mUseNativeLineBreak = aOptions.mUseNativeLineBreak;
+    mInput.mRelativeToInsertionPoint = aOptions.mRelativeToInsertionPoint;
+    MOZ_ASSERT(mInput.IsValidEventMessage(mMessage));
+  }
+
+  void InitForQueryTextContent(int64_t aOffset, uint32_t aLength,
+                               const Options& aOptions = Options()) {
+    NS_ASSERTION(mMessage == eQueryTextContent, "wrong initializer is called");
+    mInput.mOffset = aOffset;
+    mInput.mLength = aLength;
+    Init(aOptions);
+    MOZ_ASSERT(mInput.IsValidOffset());
+  }
+
+  void InitForQueryCaretRect(int64_t aOffset,
+                             const Options& aOptions = Options()) {
+    NS_ASSERTION(mMessage == eQueryCaretRect, "wrong initializer is called");
+    mInput.mOffset = aOffset;
+    Init(aOptions);
+    MOZ_ASSERT(mInput.IsValidOffset());
+  }
+
+  void InitForQueryTextRect(int64_t aOffset, uint32_t aLength,
+                            const Options& aOptions = Options()) {
+    NS_ASSERTION(mMessage == eQueryTextRect, "wrong initializer is called");
+    mInput.mOffset = aOffset;
+    mInput.mLength = aLength;
+    Init(aOptions);
+    MOZ_ASSERT(mInput.IsValidOffset());
+  }
+
+  void InitForQuerySelectedText(SelectionType aSelectionType,
+                                const Options& aOptions = Options()) {
+    MOZ_ASSERT(mMessage == eQuerySelectedText);
+    MOZ_ASSERT(aSelectionType != SelectionType::eNone);
+    mInput.mSelectionType = aSelectionType;
+    Init(aOptions);
+  }
+
+  void InitForQueryDOMWidgetHittest(
+      const mozilla::LayoutDeviceIntPoint& aPoint) {
+    NS_ASSERTION(mMessage == eQueryDOMWidgetHittest,
+                 "wrong initializer is called");
+    mRefPoint = aPoint;
+  }
+
+  void InitForQueryTextRectArray(uint32_t aOffset, uint32_t aLength,
+                                 const Options& aOptions = Options()) {
+    NS_ASSERTION(mMessage == eQueryTextRectArray,
+                 "wrong initializer is called");
+    mInput.mOffset = aOffset;
+    mInput.mLength = aLength;
+    Init(aOptions);
+  }
+
+  bool NeedsToFlushLayout() const { return mNeedsToFlushLayout; }
+
+  void RequestFontRanges() {
+    MOZ_ASSERT(mMessage == eQueryTextContent);
+    mWithFontRanges = true;
+  }
+
+  bool Succeeded() const {
+    if (mReply.isNothing()) {
+      return false;
+    }
+    switch (mMessage) {
+      case eQuerySelectedText:
+        return mReply->mOffsetAndData.isSome() ||
+               mInput.mSelectionType != SelectionType::eNormal;
+      case eQueryTextContent:
+      case eQueryTextRect:
+      case eQueryCaretRect:
+        return mReply->mOffsetAndData.isSome();
+      default:
+        return true;
+    }
+  }
+
+  bool Failed() const { return !Succeeded(); }
+
+  bool FoundSelection() const {
+    MOZ_ASSERT(mMessage == eQuerySelectedText);
+    return Succeeded() && mReply->mOffsetAndData.isSome();
+  }
+
+  bool FoundChar() const {
+    MOZ_ASSERT(mMessage == eQueryCharacterAtPoint);
+    return Succeeded() && mReply->mOffsetAndData.isSome();
+  }
+
+  bool FoundTentativeCaretOffset() const {
+    MOZ_ASSERT(mMessage == eQueryCharacterAtPoint);
+    return Succeeded() && mReply->mTentativeCaretOffset.isSome();
+  }
+
+  bool DidNotFindSelection() const {
+    MOZ_ASSERT(mMessage == eQuerySelectedText);
+    return Failed() || mReply->mOffsetAndData.isNothing();
+  }
+
+  bool DidNotFindChar() const {
+    MOZ_ASSERT(mMessage == eQueryCharacterAtPoint);
+    return Failed() || mReply->mOffsetAndData.isNothing();
+  }
+
+  bool DidNotFindTentativeCaretOffset() const {
+    MOZ_ASSERT(mMessage == eQueryCharacterAtPoint);
+    return Failed() || mReply->mTentativeCaretOffset.isNothing();
+  }
+
+  bool mUseNativeLineBreak;
+  bool mWithFontRanges;
+  bool mNeedsToFlushLayout;
+  struct Input final {
+    uint32_t EndOffset() const {
+      CheckedInt<uint32_t> endOffset = CheckedInt<uint32_t>(mOffset) + mLength;
+      return NS_WARN_IF(!endOffset.isValid()) ? UINT32_MAX : endOffset.value();
+    }
+
+    int64_t mOffset;
+    uint32_t mLength;
+    SelectionType mSelectionType;
+    // If mOffset is true, mOffset is relative to the start offset of
+    // composition if there is, otherwise, the start of the first selection
+    // range.
+    bool mRelativeToInsertionPoint;
+
+    Input()
+        : mOffset(0),
+          mLength(0),
+          mSelectionType(SelectionType::eNormal),
+          mRelativeToInsertionPoint(false) {}
+
+    bool IsValidOffset() const {
+      return mRelativeToInsertionPoint || mOffset >= 0;
+    }
+    bool IsValidEventMessage(EventMessage aEventMessage) const {
+      if (!mRelativeToInsertionPoint) {
+        return true;
+      }
+      switch (aEventMessage) {
+        case eQueryTextContent:
+        case eQueryCaretRect:
+        case eQueryTextRect:
+          return true;
+        default:
+          return false;
+      }
+    }
+    bool MakeOffsetAbsolute(uint32_t aInsertionPointOffset) {
+      if (NS_WARN_IF(!mRelativeToInsertionPoint)) {
+        return true;
+      }
+      mRelativeToInsertionPoint = false;
+      // If mOffset + aInsertionPointOffset becomes negative value,
+      // we should assume the absolute offset is 0.
+      if (mOffset < 0 && -mOffset > aInsertionPointOffset) {
+        mOffset = 0;
+        return true;
+      }
+      // Otherwise, we don't allow too large offset.
+      CheckedInt<uint32_t> absOffset(mOffset + aInsertionPointOffset);
+      if (NS_WARN_IF(!absOffset.isValid())) {
+        mOffset = UINT32_MAX;
+        return false;
+      }
+      mOffset = absOffset.value();
+      return true;
+    }
+  } mInput;
+
+  struct Reply final {
+    EventMessage const mEventMessage;
+    void* mContentsRoot;
+    Maybe<OffsetAndData<uint32_t>> mOffsetAndData;
+    // mTentativeCaretOffset is used by only eQueryCharacterAtPoint.
+    // This is the offset where caret would be if user clicked at the mRefPoint.
+    Maybe<uint32_t> mTentativeCaretOffset;
+    // mRect is used by eQueryTextRect, eQueryCaretRect, eQueryCharacterAtPoint
+    // and eQueryEditorRect. The coordinates is system coordinates relative to
+    // the top level widget of mFocusedWidget.  E.g., if a <xul:panel> which
+    // is owned by a window has focused editor, the offset of mRect is relative
+    // to the owner window, not the <xul:panel>.
+    mozilla::LayoutDeviceIntRect mRect;
+    // The return widget has the caret. This is set at all query events.
+    nsIWidget* mFocusedWidget;
+    // mozilla::WritingMode value at the end (focus) of the selection
+    mozilla::WritingMode mWritingMode;
+    // Used by eQuerySelectionAsTransferable
+    nsCOMPtr<nsITransferable> mTransferable;
+    // Used by eQueryTextContent with font ranges requested
+    CopyableAutoTArray<mozilla::FontRange, 1> mFontRanges;
+    // Used by eQueryTextRectArray
+    CopyableTArray<mozilla::LayoutDeviceIntRect> mRectArray;
+    // true if selection is reversed (end < start)
+    bool mReversed;
+    // true if the selection exists
+    bool mHasSelection;
+    // true if DOM element under mouse belongs to widget
+    bool mWidgetIsHit;
+
+    Reply() = delete;
+    explicit Reply(EventMessage aEventMessage)
+        : mEventMessage(aEventMessage),
+          mContentsRoot(nullptr),
+          mFocusedWidget(nullptr),
+          mReversed(false),
+          mHasSelection(false),
+          mWidgetIsHit(false) {}
+
+    // Don't allow to copy/move because of `mEventMessage`.
+    Reply(const Reply& aOther) = delete;
+    Reply(Reply&& aOther) = delete;
+    Reply& operator=(const Reply& aOther) = delete;
+    Reply& operator=(Reply&& aOther) = delete;
+
+    MOZ_NEVER_INLINE_DEBUG uint32_t StartOffset() const {
+      MOZ_ASSERT(mOffsetAndData.isSome());
+      return mOffsetAndData->StartOffset();
+    }
+    MOZ_NEVER_INLINE_DEBUG uint32_t EndOffset() const {
+      MOZ_ASSERT(mOffsetAndData.isSome());
+      return mOffsetAndData->EndOffset();
+    }
+    MOZ_NEVER_INLINE_DEBUG uint32_t DataLength() const {
+      MOZ_ASSERT(mOffsetAndData.isSome() ||
+                 mEventMessage == eQuerySelectedText);
+      return mOffsetAndData.isSome() ? mOffsetAndData->Length() : 0;
+    }
+    MOZ_NEVER_INLINE_DEBUG uint32_t SelectionStartOffset() const {
+      MOZ_ASSERT(mEventMessage == eQuerySelectedText);
+      MOZ_ASSERT(mOffsetAndData.isSome());
+      return StartOffset() + (mReversed ? DataLength() : 0);
+    }
+
+    MOZ_NEVER_INLINE_DEBUG uint32_t SelectionEndOffset() const {
+      MOZ_ASSERT(mEventMessage == eQuerySelectedText);
+      MOZ_ASSERT(mOffsetAndData.isSome());
+      return StartOffset() + (mReversed ? 0 : DataLength());
+    }
+
+    const WritingMode& WritingModeRef() const {
+      MOZ_ASSERT(mEventMessage == eQuerySelectedText ||
+                 mEventMessage == eQueryCaretRect ||
+                 mEventMessage == eQueryTextRect);
+      MOZ_ASSERT(mOffsetAndData.isSome() ||
+                 mEventMessage == eQuerySelectedText);
+      return mWritingMode;
+    }
+
+    MOZ_NEVER_INLINE_DEBUG const nsString& DataRef() const {
+      MOZ_ASSERT(mOffsetAndData.isSome() ||
+                 mEventMessage == eQuerySelectedText);
+      return mOffsetAndData.isSome() ? mOffsetAndData->DataRef()
+                                     : EmptyString();
+    }
+    MOZ_NEVER_INLINE_DEBUG bool IsDataEmpty() const {
+      MOZ_ASSERT(mOffsetAndData.isSome() ||
+                 mEventMessage == eQuerySelectedText);
+      return mOffsetAndData.isSome() ? mOffsetAndData->IsDataEmpty() : true;
+    }
+    MOZ_NEVER_INLINE_DEBUG bool IsOffsetInRange(uint32_t aOffset) const {
+      MOZ_ASSERT(mOffsetAndData.isSome() ||
+                 mEventMessage == eQuerySelectedText);
+      return mOffsetAndData.isSome() ? mOffsetAndData->IsOffsetInRange(aOffset)
+                                     : false;
+    }
+    MOZ_NEVER_INLINE_DEBUG bool IsOffsetInRangeOrEndOffset(
+        uint32_t aOffset) const {
+      MOZ_ASSERT(mOffsetAndData.isSome() ||
+                 mEventMessage == eQuerySelectedText);
+      return mOffsetAndData.isSome()
+                 ? mOffsetAndData->IsOffsetInRangeOrEndOffset(aOffset)
+                 : false;
+    }
+    MOZ_NEVER_INLINE_DEBUG void TruncateData(uint32_t aLength = 0) {
+      MOZ_ASSERT(mOffsetAndData.isSome());
+      mOffsetAndData->TruncateData(aLength);
+    }
+
+    friend std::ostream& operator<<(std::ostream& aStream,
+                                    const Reply& aReply) {
+      aStream << "{ ";
+      if (aReply.mEventMessage == eQuerySelectedText ||
+          aReply.mEventMessage == eQueryTextContent ||
+          aReply.mEventMessage == eQueryTextRect ||
+          aReply.mEventMessage == eQueryCaretRect ||
+          aReply.mEventMessage == eQueryCharacterAtPoint) {
+        aStream << "mOffsetAndData=" << ToString(aReply.mOffsetAndData).c_str()
+                << ", ";
+        if (aReply.mEventMessage == eQueryCharacterAtPoint) {
+          aStream << "mTentativeCaretOffset="
+                  << ToString(aReply.mTentativeCaretOffset).c_str() << ", ";
+        }
+      }
+      aStream << "mHasSelection=" << (aReply.mHasSelection ? "true" : "false");
+      if (aReply.mHasSelection) {
+        if (aReply.mEventMessage == eQuerySelectedText) {
+          aStream << ", mReversed=" << (aReply.mReversed ? "true" : "false");
+        }
+        if (aReply.mEventMessage == eQuerySelectionAsTransferable) {
+          aStream << ", mTransferable=0x" << aReply.mTransferable;
+        }
+      }
+      if (aReply.mEventMessage == eQuerySelectedText ||
+          aReply.mEventMessage == eQueryTextRect ||
+          aReply.mEventMessage == eQueryCaretRect) {
+        aStream << ", mWritingMode=" << ToString(aReply.mWritingMode).c_str();
+      }
+      aStream << ", mContentsRoot=0x" << aReply.mContentsRoot
+              << ", mFocusedWidget=0x" << aReply.mFocusedWidget;
+      if (aReply.mEventMessage == eQueryTextContent) {
+        aStream << ", mFontRanges={ Length()=" << aReply.mFontRanges.Length()
+                << " }";
+      } else if (aReply.mEventMessage == eQueryTextRect ||
+                 aReply.mEventMessage == eQueryCaretRect ||
+                 aReply.mEventMessage == eQueryCharacterAtPoint) {
+        aStream << ", mRect=" << ToString(aReply.mRect).c_str();
+      } else if (aReply.mEventMessage == eQueryTextRectArray) {
+        aStream << ", mRectArray={ Length()=" << aReply.mRectArray.Length()
+                << " }";
+      } else if (aReply.mEventMessage == eQueryDOMWidgetHittest) {
+        aStream << ", mWidgetIsHit="
+                << (aReply.mWidgetIsHit ? "true" : "false");
+      }
+      return aStream << " }";
+    }
+  };
+
+  void EmplaceReply() { mReply.emplace(mMessage); }
+  Maybe<Reply> mReply;
+
+  // values of mComputedScrollAction
+  enum { SCROLL_ACTION_NONE, SCROLL_ACTION_LINE, SCROLL_ACTION_PAGE };
+};
+
+/******************************************************************************
+ * mozilla::WidgetSelectionEvent
+ ******************************************************************************/
+
+class WidgetSelectionEvent : public WidgetGUIEvent {
+ private:
+  friend class mozilla::dom::PBrowserParent;
+  friend class mozilla::dom::PBrowserChild;
+
+  WidgetSelectionEvent()
+      : mOffset(0),
+        mLength(0),
+        mReversed(false),
+        mExpandToClusterBoundary(true),
+        mSucceeded(false),
+        mUseNativeLineBreak(true),
+        mReason(nsISelectionListener::NO_REASON) {}
+
+ public:
+  virtual WidgetSelectionEvent* AsSelectionEvent() override { return this; }
+
+  WidgetSelectionEvent(bool aIsTrusted, EventMessage aMessage,
+                       nsIWidget* aWidget)
+      : WidgetGUIEvent(aIsTrusted, aMessage, aWidget, eSelectionEventClass),
+        mOffset(0),
+        mLength(0),
+        mReversed(false),
+        mExpandToClusterBoundary(true),
+        mSucceeded(false),
+        mUseNativeLineBreak(true),
+        mReason(nsISelectionListener::NO_REASON) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    // This event isn't an internal event of any DOM event.
+    NS_ASSERTION(!IsAllowedToDispatchDOMEvent(),
+                 "WidgetSelectionEvent needs to support Duplicate()");
+    MOZ_CRASH("WidgetSelectionEvent doesn't support Duplicate()");
+    return nullptr;
+  }
+
+  // Start offset of selection
+  uint32_t mOffset;
+  // Length of selection
+  uint32_t mLength;
+  // Selection "anchor" should be in front
+  bool mReversed;
+  // Cluster-based or character-based
+  bool mExpandToClusterBoundary;
+  // true if setting selection succeeded.
+  bool mSucceeded;
+  // true if native line breaks are used for mOffset and mLength
+  bool mUseNativeLineBreak;
+  // Fennec provides eSetSelection reason codes for downstream
+  // use in AccessibleCaret visibility logic.
+  int16_t mReason;
+};
+
+/******************************************************************************
+ * mozilla::InternalEditorInputEvent
+ ******************************************************************************/
+
+class InternalEditorInputEvent : public InternalUIEvent {
+ private:
+  InternalEditorInputEvent()
+      : mData(VoidString()),
+        mInputType(EditorInputType::eUnknown),
+        mIsComposing(false) {}
+
+ public:
+  virtual InternalEditorInputEvent* AsEditorInputEvent() override {
+    return this;
+  }
+
+  InternalEditorInputEvent(bool aIsTrusted, EventMessage aMessage,
+                           nsIWidget* aWidget = nullptr)
+      : InternalUIEvent(aIsTrusted, aMessage, aWidget, eEditorInputEventClass),
+        mData(VoidString()),
+        mInputType(EditorInputType::eUnknown) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eEditorInputEventClass,
+               "Duplicate() must be overridden by sub class");
+    // Not copying widget, it is a weak reference.
+    InternalEditorInputEvent* result =
+        new InternalEditorInputEvent(false, mMessage, nullptr);
+    result->AssignEditorInputEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  nsString mData;
+  RefPtr<dom::DataTransfer> mDataTransfer;
+  OwningNonNullStaticRangeArray mTargetRanges;
+
+  EditorInputType mInputType;
+
+  bool mIsComposing;
+
+  void AssignEditorInputEventData(const InternalEditorInputEvent& aEvent,
+                                  bool aCopyTargets) {
+    AssignUIEventData(aEvent, aCopyTargets);
+
+    mData = aEvent.mData;
+    mDataTransfer = aEvent.mDataTransfer;
+    mTargetRanges = aEvent.mTargetRanges.Clone();
+    mInputType = aEvent.mInputType;
+    mIsComposing = aEvent.mIsComposing;
+  }
+
+  void GetDOMInputTypeName(nsAString& aInputTypeName) {
+    GetDOMInputTypeName(mInputType, aInputTypeName);
+  }
+  static void GetDOMInputTypeName(EditorInputType aInputType,
+                                  nsAString& aInputTypeName);
+  static EditorInputType GetEditorInputType(const nsAString& aInputType);
+
+  static void Shutdown();
+
+ private:
+  static const char16_t* const kInputTypeNames[];
+  typedef nsDataHashtable<nsStringHashKey, EditorInputType> InputTypeHashtable;
+  static InputTypeHashtable* sInputTypeHashtable;
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_TextEvents_h__