Adding upstream version 124.0.1.upstream/124.0.1

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

1 files changed, 5442 insertions, 0 deletions

diff --git a/widget/windows/KeyboardLayout.cpp b/widget/windows/KeyboardLayout.cpp
new file mode 100644
index 0000000000..3b59aa9319
--- /dev/null
+++ b/widget/windows/KeyboardLayout.cpp
@@ -0,0 +1,5442 @@
+/* -*- 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/. */
+
+#include "mozilla/Logging.h"
+
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/AutoRestore.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/MiscEvents.h"
+#include "mozilla/StaticPrefs_ui.h"
+#include "mozilla/TextEvents.h"
+#include "mozilla/widget/WinRegistry.h"
+
+#include "nsExceptionHandler.h"
+#include "nsGkAtoms.h"
+#include "nsIUserIdleServiceInternal.h"
+#include "nsIWindowsRegKey.h"
+#include "nsPrintfCString.h"
+#include "nsReadableUtils.h"
+#include "nsServiceManagerUtils.h"
+#include "nsTArray.h"
+#include "nsUnicharUtils.h"
+#include "nsWindowDbg.h"
+
+#include "KeyboardLayout.h"
+#include "WidgetUtils.h"
+#include "WinUtils.h"
+
+#include "npapi.h"
+
+#include <windows.h>
+#include <winnls.h>
+#include <winuser.h>
+#include <algorithm>
+
+#ifndef WINABLEAPI
+#  include <winable.h>
+#endif
+
+// For collecting other people's log, tell them `MOZ_LOG=KeyboardHandler:4,sync`
+// rather than `MOZ_LOG=KeyboardHandler:5,sync` since using `5` may create too
+// big file.
+// Therefore you shouldn't use `LogLevel::Verbose` for logging usual behavior.
+mozilla::LazyLogModule gKeyLog("KeyboardHandler");
+
+namespace mozilla {
+namespace widget {
+
+static const char* const kVirtualKeyName[] = {
+    "NULL",
+    "VK_LBUTTON",
+    "VK_RBUTTON",
+    "VK_CANCEL",
+    "VK_MBUTTON",
+    "VK_XBUTTON1",
+    "VK_XBUTTON2",
+    "0x07",
+    "VK_BACK",
+    "VK_TAB",
+    "0x0A",
+    "0x0B",
+    "VK_CLEAR",
+    "VK_RETURN",
+    "0x0E",
+    "0x0F",
+
+    "VK_SHIFT",
+    "VK_CONTROL",
+    "VK_MENU",
+    "VK_PAUSE",
+    "VK_CAPITAL",
+    "VK_KANA, VK_HANGUL",
+    "0x16",
+    "VK_JUNJA",
+    "VK_FINAL",
+    "VK_HANJA, VK_KANJI",
+    "0x1A",
+    "VK_ESCAPE",
+    "VK_CONVERT",
+    "VK_NONCONVERT",
+    "VK_ACCEPT",
+    "VK_MODECHANGE",
+
+    "VK_SPACE",
+    "VK_PRIOR",
+    "VK_NEXT",
+    "VK_END",
+    "VK_HOME",
+    "VK_LEFT",
+    "VK_UP",
+    "VK_RIGHT",
+    "VK_DOWN",
+    "VK_SELECT",
+    "VK_PRINT",
+    "VK_EXECUTE",
+    "VK_SNAPSHOT",
+    "VK_INSERT",
+    "VK_DELETE",
+    "VK_HELP",
+
+    "VK_0",
+    "VK_1",
+    "VK_2",
+    "VK_3",
+    "VK_4",
+    "VK_5",
+    "VK_6",
+    "VK_7",
+    "VK_8",
+    "VK_9",
+    "0x3A",
+    "0x3B",
+    "0x3C",
+    "0x3D",
+    "0x3E",
+    "0x3F",
+
+    "0x40",
+    "VK_A",
+    "VK_B",
+    "VK_C",
+    "VK_D",
+    "VK_E",
+    "VK_F",
+    "VK_G",
+    "VK_H",
+    "VK_I",
+    "VK_J",
+    "VK_K",
+    "VK_L",
+    "VK_M",
+    "VK_N",
+    "VK_O",
+
+    "VK_P",
+    "VK_Q",
+    "VK_R",
+    "VK_S",
+    "VK_T",
+    "VK_U",
+    "VK_V",
+    "VK_W",
+    "VK_X",
+    "VK_Y",
+    "VK_Z",
+    "VK_LWIN",
+    "VK_RWIN",
+    "VK_APPS",
+    "0x5E",
+    "VK_SLEEP",
+
+    "VK_NUMPAD0",
+    "VK_NUMPAD1",
+    "VK_NUMPAD2",
+    "VK_NUMPAD3",
+    "VK_NUMPAD4",
+    "VK_NUMPAD5",
+    "VK_NUMPAD6",
+    "VK_NUMPAD7",
+    "VK_NUMPAD8",
+    "VK_NUMPAD9",
+    "VK_MULTIPLY",
+    "VK_ADD",
+    "VK_SEPARATOR",
+    "VK_SUBTRACT",
+    "VK_DECIMAL",
+    "VK_DIVIDE",
+
+    "VK_F1",
+    "VK_F2",
+    "VK_F3",
+    "VK_F4",
+    "VK_F5",
+    "VK_F6",
+    "VK_F7",
+    "VK_F8",
+    "VK_F9",
+    "VK_F10",
+    "VK_F11",
+    "VK_F12",
+    "VK_F13",
+    "VK_F14",
+    "VK_F15",
+    "VK_F16",
+
+    "VK_F17",
+    "VK_F18",
+    "VK_F19",
+    "VK_F20",
+    "VK_F21",
+    "VK_F22",
+    "VK_F23",
+    "VK_F24",
+    "0x88",
+    "0x89",
+    "0x8A",
+    "0x8B",
+    "0x8C",
+    "0x8D",
+    "0x8E",
+    "0x8F",
+
+    "VK_NUMLOCK",
+    "VK_SCROLL",
+    "VK_OEM_NEC_EQUAL, VK_OEM_FJ_JISHO",
+    "VK_OEM_FJ_MASSHOU",
+    "VK_OEM_FJ_TOUROKU",
+    "VK_OEM_FJ_LOYA",
+    "VK_OEM_FJ_ROYA",
+    "0x97",
+    "0x98",
+    "0x99",
+    "0x9A",
+    "0x9B",
+    "0x9C",
+    "0x9D",
+    "0x9E",
+    "0x9F",
+
+    "VK_LSHIFT",
+    "VK_RSHIFT",
+    "VK_LCONTROL",
+    "VK_RCONTROL",
+    "VK_LMENU",
+    "VK_RMENU",
+    "VK_BROWSER_BACK",
+    "VK_BROWSER_FORWARD",
+    "VK_BROWSER_REFRESH",
+    "VK_BROWSER_STOP",
+    "VK_BROWSER_SEARCH",
+    "VK_BROWSER_FAVORITES",
+    "VK_BROWSER_HOME",
+    "VK_VOLUME_MUTE",
+    "VK_VOLUME_DOWN",
+    "VK_VOLUME_UP",
+
+    "VK_MEDIA_NEXT_TRACK",
+    "VK_MEDIA_PREV_TRACK",
+    "VK_MEDIA_STOP",
+    "VK_MEDIA_PLAY_PAUSE",
+    "VK_LAUNCH_MAIL",
+    "VK_LAUNCH_MEDIA_SELECT",
+    "VK_LAUNCH_APP1",
+    "VK_LAUNCH_APP2",
+    "0xB8",
+    "0xB9",
+    "VK_OEM_1",
+    "VK_OEM_PLUS",
+    "VK_OEM_COMMA",
+    "VK_OEM_MINUS",
+    "VK_OEM_PERIOD",
+    "VK_OEM_2",
+
+    "VK_OEM_3",
+    "VK_ABNT_C1",
+    "VK_ABNT_C2",
+    "0xC3",
+    "0xC4",
+    "0xC5",
+    "0xC6",
+    "0xC7",
+    "0xC8",
+    "0xC9",
+    "0xCA",
+    "0xCB",
+    "0xCC",
+    "0xCD",
+    "0xCE",
+    "0xCF",
+
+    "0xD0",
+    "0xD1",
+    "0xD2",
+    "0xD3",
+    "0xD4",
+    "0xD5",
+    "0xD6",
+    "0xD7",
+    "0xD8",
+    "0xD9",
+    "0xDA",
+    "VK_OEM_4",
+    "VK_OEM_5",
+    "VK_OEM_6",
+    "VK_OEM_7",
+    "VK_OEM_8",
+
+    "0xE0",
+    "VK_OEM_AX",
+    "VK_OEM_102",
+    "VK_ICO_HELP",
+    "VK_ICO_00",
+    "VK_PROCESSKEY",
+    "VK_ICO_CLEAR",
+    "VK_PACKET",
+    "0xE8",
+    "VK_OEM_RESET",
+    "VK_OEM_JUMP",
+    "VK_OEM_PA1",
+    "VK_OEM_PA2",
+    "VK_OEM_PA3",
+    "VK_OEM_WSCTRL",
+    "VK_OEM_CUSEL",
+
+    "VK_OEM_ATTN",
+    "VK_OEM_FINISH",
+    "VK_OEM_COPY",
+    "VK_OEM_AUTO",
+    "VK_OEM_ENLW",
+    "VK_OEM_BACKTAB",
+    "VK_ATTN",
+    "VK_CRSEL",
+    "VK_EXSEL",
+    "VK_EREOF",
+    "VK_PLAY",
+    "VK_ZOOM",
+    "VK_NONAME",
+    "VK_PA1",
+    "VK_OEM_CLEAR",
+    "0xFF"};
+
+static_assert(sizeof(kVirtualKeyName) / sizeof(const char*) == 0x100,
+              "The virtual key name must be defined just 256 keys");
+
+static const char* GetBoolName(bool aBool) { return aBool ? "true" : "false"; }
+
+static const nsCString GetCharacterCodeName(WPARAM aCharCode) {
+  switch (aCharCode) {
+    case 0x0000:
+      return "NULL (0x0000)"_ns;
+    case 0x0008:
+      return "BACKSPACE (0x0008)"_ns;
+    case 0x0009:
+      return "CHARACTER TABULATION (0x0009)"_ns;
+    case 0x000A:
+      return "LINE FEED (0x000A)"_ns;
+    case 0x000B:
+      return "LINE TABULATION (0x000B)"_ns;
+    case 0x000C:
+      return "FORM FEED (0x000C)"_ns;
+    case 0x000D:
+      return "CARRIAGE RETURN (0x000D)"_ns;
+    case 0x0018:
+      return "CANCEL (0x0018)"_ns;
+    case 0x001B:
+      return "ESCAPE (0x001B)"_ns;
+    case 0x0020:
+      return "SPACE (0x0020)"_ns;
+    case 0x007F:
+      return "DELETE (0x007F)"_ns;
+    case 0x00A0:
+      return "NO-BREAK SPACE (0x00A0)"_ns;
+    case 0x00AD:
+      return "SOFT HYPHEN (0x00AD)"_ns;
+    case 0x2000:
+      return "EN QUAD (0x2000)"_ns;
+    case 0x2001:
+      return "EM QUAD (0x2001)"_ns;
+    case 0x2002:
+      return "EN SPACE (0x2002)"_ns;
+    case 0x2003:
+      return "EM SPACE (0x2003)"_ns;
+    case 0x2004:
+      return "THREE-PER-EM SPACE (0x2004)"_ns;
+    case 0x2005:
+      return "FOUR-PER-EM SPACE (0x2005)"_ns;
+    case 0x2006:
+      return "SIX-PER-EM SPACE (0x2006)"_ns;
+    case 0x2007:
+      return "FIGURE SPACE (0x2007)"_ns;
+    case 0x2008:
+      return "PUNCTUATION SPACE (0x2008)"_ns;
+    case 0x2009:
+      return "THIN SPACE (0x2009)"_ns;
+    case 0x200A:
+      return "HAIR SPACE (0x200A)"_ns;
+    case 0x200B:
+      return "ZERO WIDTH SPACE (0x200B)"_ns;
+    case 0x200C:
+      return "ZERO WIDTH NON-JOINER (0x200C)"_ns;
+    case 0x200D:
+      return "ZERO WIDTH JOINER (0x200D)"_ns;
+    case 0x200E:
+      return "LEFT-TO-RIGHT MARK (0x200E)"_ns;
+    case 0x200F:
+      return "RIGHT-TO-LEFT MARK (0x200F)"_ns;
+    case 0x2029:
+      return "PARAGRAPH SEPARATOR (0x2029)"_ns;
+    case 0x202A:
+      return "LEFT-TO-RIGHT EMBEDDING (0x202A)"_ns;
+    case 0x202B:
+      return "RIGHT-TO-LEFT EMBEDDING (0x202B)"_ns;
+    case 0x202D:
+      return "LEFT-TO-RIGHT OVERRIDE (0x202D)"_ns;
+    case 0x202E:
+      return "RIGHT-TO-LEFT OVERRIDE (0x202E)"_ns;
+    case 0x202F:
+      return "NARROW NO-BREAK SPACE (0x202F)"_ns;
+    case 0x205F:
+      return "MEDIUM MATHEMATICAL SPACE (0x205F)"_ns;
+    case 0x2060:
+      return "WORD JOINER (0x2060)"_ns;
+    case 0x2066:
+      return "LEFT-TO-RIGHT ISOLATE (0x2066)"_ns;
+    case 0x2067:
+      return "RIGHT-TO-LEFT ISOLATE (0x2067)"_ns;
+    case 0x3000:
+      return "IDEOGRAPHIC SPACE (0x3000)"_ns;
+    case 0xFEFF:
+      return "ZERO WIDTH NO-BREAK SPACE (0xFEFF)"_ns;
+    default: {
+      if (aCharCode < ' ' || (aCharCode >= 0x80 && aCharCode < 0xA0)) {
+        return nsPrintfCString("control (0x%04zX)", aCharCode);
+      }
+      if (NS_IS_HIGH_SURROGATE(aCharCode)) {
+        return nsPrintfCString("high surrogate (0x%04zX)", aCharCode);
+      }
+      if (NS_IS_LOW_SURROGATE(aCharCode)) {
+        return nsPrintfCString("low surrogate (0x%04zX)", aCharCode);
+      }
+      return IS_IN_BMP(aCharCode)
+                 ? nsPrintfCString(
+                       "'%s' (0x%04zX)",
+                       NS_ConvertUTF16toUTF8(nsAutoString(aCharCode)).get(),
+                       aCharCode)
+                 : nsPrintfCString(
+                       "'%s' (0x%08zX)",
+                       NS_ConvertUTF16toUTF8(nsAutoString(aCharCode)).get(),
+                       aCharCode);
+    }
+  }
+}
+
+static const nsCString GetKeyLocationName(uint32_t aLocation) {
+  switch (aLocation) {
+    case eKeyLocationLeft:
+      return "KEY_LOCATION_LEFT"_ns;
+    case eKeyLocationRight:
+      return "KEY_LOCATION_RIGHT"_ns;
+    case eKeyLocationStandard:
+      return "KEY_LOCATION_STANDARD"_ns;
+    case eKeyLocationNumpad:
+      return "KEY_LOCATION_NUMPAD"_ns;
+    default:
+      return nsPrintfCString("Unknown (0x%04X)", aLocation);
+  }
+}
+
+static const nsCString GetCharacterCodeNames(const char16_t* aChars,
+                                             uint32_t aLength) {
+  if (!aLength) {
+    return ""_ns;
+  }
+  nsCString result;
+  result.AssignLiteral("\"");
+  StringJoinAppend(result, ", "_ns, Span{aChars, aLength},
+                   [](nsACString& dest, const char16_t charValue) {
+                     dest.Append(GetCharacterCodeName(charValue));
+                   });
+  result.AppendLiteral("\"");
+  return result;
+}
+
+static const nsCString GetCharacterCodeNames(
+    const UniCharsAndModifiers& aUniCharsAndModifiers) {
+  if (aUniCharsAndModifiers.IsEmpty()) {
+    return ""_ns;
+  }
+  nsCString result;
+  result.AssignLiteral("\"");
+  StringJoinAppend(result, ", "_ns, Span{aUniCharsAndModifiers.ToString()},
+                   [](nsACString& dest, const char16_t charValue) {
+                     dest.Append(GetCharacterCodeName(charValue));
+                   });
+  result.AppendLiteral("\"");
+  return result;
+}
+
+class MOZ_STACK_CLASS GetShiftStateName final : public nsAutoCString {
+ public:
+  explicit GetShiftStateName(VirtualKey::ShiftState aShiftState) {
+    if (!aShiftState) {
+      AssignLiteral("none");
+      return;
+    }
+    if (aShiftState & VirtualKey::STATE_SHIFT) {
+      AssignLiteral("Shift");
+      aShiftState &= ~VirtualKey::STATE_SHIFT;
+    }
+    if (aShiftState & VirtualKey::STATE_CONTROL) {
+      MaybeAppendSeparator();
+      AssignLiteral("Ctrl");
+      aShiftState &= ~VirtualKey::STATE_CONTROL;
+    }
+    if (aShiftState & VirtualKey::STATE_ALT) {
+      MaybeAppendSeparator();
+      AssignLiteral("Alt");
+      aShiftState &= ~VirtualKey::STATE_ALT;
+    }
+    if (aShiftState & VirtualKey::STATE_CAPSLOCK) {
+      MaybeAppendSeparator();
+      AssignLiteral("CapsLock");
+      aShiftState &= ~VirtualKey::STATE_CAPSLOCK;
+    }
+    MOZ_ASSERT(!aShiftState);
+  }
+
+ private:
+  void MaybeAppendSeparator() {
+    if (!IsEmpty()) {
+      AppendLiteral(" | ");
+    }
+  }
+};
+
+static const nsCString GetMessageName(UINT aMessage) {
+  switch (aMessage) {
+    case WM_NULL:
+      return "WM_NULL"_ns;
+    case WM_KEYDOWN:
+      return "WM_KEYDOWN"_ns;
+    case WM_KEYUP:
+      return "WM_KEYUP"_ns;
+    case WM_SYSKEYDOWN:
+      return "WM_SYSKEYDOWN"_ns;
+    case WM_SYSKEYUP:
+      return "WM_SYSKEYUP"_ns;
+    case WM_CHAR:
+      return "WM_CHAR"_ns;
+    case WM_UNICHAR:
+      return "WM_UNICHAR"_ns;
+    case WM_SYSCHAR:
+      return "WM_SYSCHAR"_ns;
+    case WM_DEADCHAR:
+      return "WM_DEADCHAR"_ns;
+    case WM_SYSDEADCHAR:
+      return "WM_SYSDEADCHAR"_ns;
+    case WM_APPCOMMAND:
+      return "WM_APPCOMMAND"_ns;
+    case WM_QUIT:
+      return "WM_QUIT"_ns;
+    default:
+      return nsPrintfCString("Unknown Message (0x%04X)", aMessage);
+  }
+}
+
+static const nsCString GetVirtualKeyCodeName(WPARAM aVK) {
+  if (aVK >= ArrayLength(kVirtualKeyName)) {
+    return nsPrintfCString("Invalid (0x%08zX)", aVK);
+  }
+  return nsCString(kVirtualKeyName[aVK]);
+}
+
+static const nsCString GetAppCommandName(WPARAM aCommand) {
+  switch (aCommand) {
+    case APPCOMMAND_BASS_BOOST:
+      return "APPCOMMAND_BASS_BOOST"_ns;
+    case APPCOMMAND_BASS_DOWN:
+      return "APPCOMMAND_BASS_DOWN"_ns;
+    case APPCOMMAND_BASS_UP:
+      return "APPCOMMAND_BASS_UP"_ns;
+    case APPCOMMAND_BROWSER_BACKWARD:
+      return "APPCOMMAND_BROWSER_BACKWARD"_ns;
+    case APPCOMMAND_BROWSER_FAVORITES:
+      return "APPCOMMAND_BROWSER_FAVORITES"_ns;
+    case APPCOMMAND_BROWSER_FORWARD:
+      return "APPCOMMAND_BROWSER_FORWARD"_ns;
+    case APPCOMMAND_BROWSER_HOME:
+      return "APPCOMMAND_BROWSER_HOME"_ns;
+    case APPCOMMAND_BROWSER_REFRESH:
+      return "APPCOMMAND_BROWSER_REFRESH"_ns;
+    case APPCOMMAND_BROWSER_SEARCH:
+      return "APPCOMMAND_BROWSER_SEARCH"_ns;
+    case APPCOMMAND_BROWSER_STOP:
+      return "APPCOMMAND_BROWSER_STOP"_ns;
+    case APPCOMMAND_CLOSE:
+      return "APPCOMMAND_CLOSE"_ns;
+    case APPCOMMAND_COPY:
+      return "APPCOMMAND_COPY"_ns;
+    case APPCOMMAND_CORRECTION_LIST:
+      return "APPCOMMAND_CORRECTION_LIST"_ns;
+    case APPCOMMAND_CUT:
+      return "APPCOMMAND_CUT"_ns;
+    case APPCOMMAND_DICTATE_OR_COMMAND_CONTROL_TOGGLE:
+      return "APPCOMMAND_DICTATE_OR_COMMAND_CONTROL_TOGGLE"_ns;
+    case APPCOMMAND_FIND:
+      return "APPCOMMAND_FIND"_ns;
+    case APPCOMMAND_FORWARD_MAIL:
+      return "APPCOMMAND_FORWARD_MAIL"_ns;
+    case APPCOMMAND_HELP:
+      return "APPCOMMAND_HELP"_ns;
+    case APPCOMMAND_LAUNCH_APP1:
+      return "APPCOMMAND_LAUNCH_APP1"_ns;
+    case APPCOMMAND_LAUNCH_APP2:
+      return "APPCOMMAND_LAUNCH_APP2"_ns;
+    case APPCOMMAND_LAUNCH_MAIL:
+      return "APPCOMMAND_LAUNCH_MAIL"_ns;
+    case APPCOMMAND_LAUNCH_MEDIA_SELECT:
+      return "APPCOMMAND_LAUNCH_MEDIA_SELECT"_ns;
+    case APPCOMMAND_MEDIA_CHANNEL_DOWN:
+      return "APPCOMMAND_MEDIA_CHANNEL_DOWN"_ns;
+    case APPCOMMAND_MEDIA_CHANNEL_UP:
+      return "APPCOMMAND_MEDIA_CHANNEL_UP"_ns;
+    case APPCOMMAND_MEDIA_FAST_FORWARD:
+      return "APPCOMMAND_MEDIA_FAST_FORWARD"_ns;
+    case APPCOMMAND_MEDIA_NEXTTRACK:
+      return "APPCOMMAND_MEDIA_NEXTTRACK"_ns;
+    case APPCOMMAND_MEDIA_PAUSE:
+      return "APPCOMMAND_MEDIA_PAUSE"_ns;
+    case APPCOMMAND_MEDIA_PLAY:
+      return "APPCOMMAND_MEDIA_PLAY"_ns;
+    case APPCOMMAND_MEDIA_PLAY_PAUSE:
+      return "APPCOMMAND_MEDIA_PLAY_PAUSE"_ns;
+    case APPCOMMAND_MEDIA_PREVIOUSTRACK:
+      return "APPCOMMAND_MEDIA_PREVIOUSTRACK"_ns;
+    case APPCOMMAND_MEDIA_RECORD:
+      return "APPCOMMAND_MEDIA_RECORD"_ns;
+    case APPCOMMAND_MEDIA_REWIND:
+      return "APPCOMMAND_MEDIA_REWIND"_ns;
+    case APPCOMMAND_MEDIA_STOP:
+      return "APPCOMMAND_MEDIA_STOP"_ns;
+    case APPCOMMAND_MIC_ON_OFF_TOGGLE:
+      return "APPCOMMAND_MIC_ON_OFF_TOGGLE"_ns;
+    case APPCOMMAND_MICROPHONE_VOLUME_DOWN:
+      return "APPCOMMAND_MICROPHONE_VOLUME_DOWN"_ns;
+    case APPCOMMAND_MICROPHONE_VOLUME_MUTE:
+      return "APPCOMMAND_MICROPHONE_VOLUME_MUTE"_ns;
+    case APPCOMMAND_MICROPHONE_VOLUME_UP:
+      return "APPCOMMAND_MICROPHONE_VOLUME_UP"_ns;
+    case APPCOMMAND_NEW:
+      return "APPCOMMAND_NEW"_ns;
+    case APPCOMMAND_OPEN:
+      return "APPCOMMAND_OPEN"_ns;
+    case APPCOMMAND_PASTE:
+      return "APPCOMMAND_PASTE"_ns;
+    case APPCOMMAND_PRINT:
+      return "APPCOMMAND_PRINT"_ns;
+    case APPCOMMAND_REDO:
+      return "APPCOMMAND_REDO"_ns;
+    case APPCOMMAND_REPLY_TO_MAIL:
+      return "APPCOMMAND_REPLY_TO_MAIL"_ns;
+    case APPCOMMAND_SAVE:
+      return "APPCOMMAND_SAVE"_ns;
+    case APPCOMMAND_SEND_MAIL:
+      return "APPCOMMAND_SEND_MAIL"_ns;
+    case APPCOMMAND_SPELL_CHECK:
+      return "APPCOMMAND_SPELL_CHECK"_ns;
+    case APPCOMMAND_TREBLE_DOWN:
+      return "APPCOMMAND_TREBLE_DOWN"_ns;
+    case APPCOMMAND_TREBLE_UP:
+      return "APPCOMMAND_TREBLE_UP"_ns;
+    case APPCOMMAND_UNDO:
+      return "APPCOMMAND_UNDO"_ns;
+    case APPCOMMAND_VOLUME_DOWN:
+      return "APPCOMMAND_VOLUME_DOWN"_ns;
+    case APPCOMMAND_VOLUME_MUTE:
+      return "APPCOMMAND_VOLUME_MUTE"_ns;
+    case APPCOMMAND_VOLUME_UP:
+      return "APPCOMMAND_VOLUME_UP"_ns;
+    default:
+      return nsPrintfCString("Unknown app command (0x%08zX)", aCommand);
+  }
+}
+
+static const nsCString GetAppCommandDeviceName(LPARAM aDevice) {
+  switch (aDevice) {
+    case FAPPCOMMAND_KEY:
+      return "FAPPCOMMAND_KEY"_ns;
+    case FAPPCOMMAND_MOUSE:
+      return "FAPPCOMMAND_MOUSE"_ns;
+    case FAPPCOMMAND_OEM:
+      return "FAPPCOMMAND_OEM"_ns;
+    default:
+      return nsPrintfCString("Unknown app command device (0x%04" PRIXLPTR ")",
+                             aDevice);
+  }
+};
+
+class MOZ_STACK_CLASS GetAppCommandKeysName final : public nsAutoCString {
+ public:
+  explicit GetAppCommandKeysName(WPARAM aKeys) {
+    if (aKeys & MK_CONTROL) {
+      AppendLiteral("MK_CONTROL");
+      aKeys &= ~MK_CONTROL;
+    }
+    if (aKeys & MK_LBUTTON) {
+      MaybeAppendSeparator();
+      AppendLiteral("MK_LBUTTON");
+      aKeys &= ~MK_LBUTTON;
+    }
+    if (aKeys & MK_MBUTTON) {
+      MaybeAppendSeparator();
+      AppendLiteral("MK_MBUTTON");
+      aKeys &= ~MK_MBUTTON;
+    }
+    if (aKeys & MK_RBUTTON) {
+      MaybeAppendSeparator();
+      AppendLiteral("MK_RBUTTON");
+      aKeys &= ~MK_RBUTTON;
+    }
+    if (aKeys & MK_SHIFT) {
+      MaybeAppendSeparator();
+      AppendLiteral("MK_SHIFT");
+      aKeys &= ~MK_SHIFT;
+    }
+    if (aKeys & MK_XBUTTON1) {
+      MaybeAppendSeparator();
+      AppendLiteral("MK_XBUTTON1");
+      aKeys &= ~MK_XBUTTON1;
+    }
+    if (aKeys & MK_XBUTTON2) {
+      MaybeAppendSeparator();
+      AppendLiteral("MK_XBUTTON2");
+      aKeys &= ~MK_XBUTTON2;
+    }
+    if (aKeys) {
+      MaybeAppendSeparator();
+      AppendPrintf("Unknown Flags (0x%04zX)", aKeys);
+    }
+    if (IsEmpty()) {
+      AssignLiteral("none (0x0000)");
+    }
+  }
+
+ private:
+  void MaybeAppendSeparator() {
+    if (!IsEmpty()) {
+      AppendLiteral(" | ");
+    }
+  }
+};
+
+static const nsCString ToString(const MSG& aMSG) {
+  nsCString result;
+  result.AssignLiteral("{ message=");
+  result.Append(GetMessageName(aMSG.message).get());
+  result.AppendLiteral(", ");
+  switch (aMSG.message) {
+    case WM_KEYDOWN:
+    case WM_KEYUP:
+    case WM_SYSKEYDOWN:
+    case WM_SYSKEYUP:
+      result.AppendPrintf(
+          "virtual keycode=%s, repeat count=%" PRIdLPTR
+          ", "
+          "scancode=0x%02X, extended key=%s, "
+          "context code=%s, previous key state=%s, "
+          "transition state=%s",
+          GetVirtualKeyCodeName(aMSG.wParam).get(), aMSG.lParam & 0xFFFF,
+          WinUtils::GetScanCode(aMSG.lParam),
+          GetBoolName(WinUtils::IsExtendedScanCode(aMSG.lParam)),
+          GetBoolName((aMSG.lParam & (1 << 29)) != 0),
+          GetBoolName((aMSG.lParam & (1 << 30)) != 0),
+          GetBoolName((aMSG.lParam & (1 << 31)) != 0));
+      break;
+    case WM_CHAR:
+    case WM_DEADCHAR:
+    case WM_SYSCHAR:
+    case WM_SYSDEADCHAR:
+      result.AppendPrintf(
+          "character code=%s, repeat count=%" PRIdLPTR
+          ", "
+          "scancode=0x%02X, extended key=%s, "
+          "context code=%s, previous key state=%s, "
+          "transition state=%s",
+          GetCharacterCodeName(aMSG.wParam).get(), aMSG.lParam & 0xFFFF,
+          WinUtils::GetScanCode(aMSG.lParam),
+          GetBoolName(WinUtils::IsExtendedScanCode(aMSG.lParam)),
+          GetBoolName((aMSG.lParam & (1 << 29)) != 0),
+          GetBoolName((aMSG.lParam & (1 << 30)) != 0),
+          GetBoolName((aMSG.lParam & (1 << 31)) != 0));
+      break;
+    case WM_APPCOMMAND:
+      result.AppendPrintf(
+          "window handle=0x%zx, app command=%s, device=%s, dwKeys=%s",
+          aMSG.wParam,
+          GetAppCommandName(GET_APPCOMMAND_LPARAM(aMSG.lParam)).get(),
+          GetAppCommandDeviceName(GET_DEVICE_LPARAM(aMSG.lParam)).get(),
+          GetAppCommandKeysName(GET_KEYSTATE_LPARAM(aMSG.lParam)).get());
+      break;
+    default:
+      result.AppendPrintf("wParam=%zu, lParam=%" PRIdLPTR, aMSG.wParam,
+                          aMSG.lParam);
+      break;
+  }
+  result.AppendPrintf(", hwnd=0x%p", aMSG.hwnd);
+  return result;
+}
+
+static const nsCString ToString(
+    const UniCharsAndModifiers& aUniCharsAndModifiers) {
+  if (aUniCharsAndModifiers.IsEmpty()) {
+    return "{}"_ns;
+  }
+  nsCString result;
+  result.AssignLiteral("{ ");
+  result.Append(GetCharacterCodeName(aUniCharsAndModifiers.CharAt(0)));
+  for (size_t i = 1; i < aUniCharsAndModifiers.Length(); ++i) {
+    if (aUniCharsAndModifiers.ModifiersAt(i - 1) !=
+        aUniCharsAndModifiers.ModifiersAt(i)) {
+      result.AppendLiteral(" [");
+      result.Append(GetModifiersName(aUniCharsAndModifiers.ModifiersAt(0)));
+      result.AppendLiteral("]");
+    }
+    result.AppendLiteral(", ");
+    result.Append(GetCharacterCodeName(aUniCharsAndModifiers.CharAt(i)));
+  }
+  result.AppendLiteral(" [");
+  uint32_t lastIndex = aUniCharsAndModifiers.Length() - 1;
+  result.Append(GetModifiersName(aUniCharsAndModifiers.ModifiersAt(lastIndex)));
+  result.AppendLiteral("] }");
+  return result;
+}
+
+const nsCString ToString(const ModifierKeyState& aModifierKeyState) {
+  nsCString result;
+  result.AssignLiteral("{ ");
+  result.Append(GetModifiersName(aModifierKeyState.GetModifiers()).get());
+  result.AppendLiteral(" }");
+  return result;
+}
+
+// Unique id counter associated with a keydown / keypress events. Used in
+// identifing keypress events for removal from async event dispatch queue
+// in metrofx after preventDefault is called on keydown events.
+static uint32_t sUniqueKeyEventId = 0;
+
+/*****************************************************************************
+ * mozilla::widget::ModifierKeyState
+ *****************************************************************************/
+
+ModifierKeyState::ModifierKeyState() { Update(); }
+
+ModifierKeyState::ModifierKeyState(Modifiers aModifiers)
+    : mModifiers(aModifiers) {
+  MOZ_ASSERT(!(mModifiers & MODIFIER_ALTGRAPH) || (!IsControl() && !IsAlt()),
+             "Neither MODIFIER_CONTROL nor MODIFIER_ALT should be set "
+             "if MODIFIER_ALTGRAPH is set");
+}
+
+void ModifierKeyState::Update() {
+  mModifiers = 0;
+  if (IS_VK_DOWN(VK_SHIFT)) {
+    mModifiers |= MODIFIER_SHIFT;
+  }
+  // If AltGr key (i.e., VK_RMENU on some keyboard layout) is pressed, only
+  // MODIFIER_ALTGRAPH should be set.  Otherwise, i.e., if both Ctrl and Alt
+  // keys are pressed to emulate AltGr key, MODIFIER_CONTROL and MODIFIER_ALT
+  // keys should be set separately.
+  if (IS_VK_DOWN(VK_RMENU) && KeyboardLayout::GetInstance()->HasAltGr()) {
+    mModifiers |= MODIFIER_ALTGRAPH;
+  } else {
+    if (IS_VK_DOWN(VK_CONTROL)) {
+      mModifiers |= MODIFIER_CONTROL;
+    }
+    if (IS_VK_DOWN(VK_MENU)) {
+      mModifiers |= MODIFIER_ALT;
+    }
+  }
+  if (IS_VK_DOWN(VK_LWIN) || IS_VK_DOWN(VK_RWIN)) {
+    mModifiers |= MODIFIER_META;
+  }
+  if (::GetKeyState(VK_CAPITAL) & 1) {
+    mModifiers |= MODIFIER_CAPSLOCK;
+  }
+  if (::GetKeyState(VK_NUMLOCK) & 1) {
+    mModifiers |= MODIFIER_NUMLOCK;
+  }
+  if (::GetKeyState(VK_SCROLL) & 1) {
+    mModifiers |= MODIFIER_SCROLLLOCK;
+  }
+}
+
+void ModifierKeyState::Unset(Modifiers aRemovingModifiers) {
+  mModifiers &= ~aRemovingModifiers;
+}
+
+void ModifierKeyState::Set(Modifiers aAddingModifiers) {
+  mModifiers |= aAddingModifiers;
+  MOZ_ASSERT(!(mModifiers & MODIFIER_ALTGRAPH) || (!IsControl() && !IsAlt()),
+             "Neither MODIFIER_CONTROL nor MODIFIER_ALT should be set "
+             "if MODIFIER_ALTGRAPH is set");
+}
+
+void ModifierKeyState::InitInputEvent(WidgetInputEvent& aInputEvent) const {
+  aInputEvent.mModifiers = mModifiers;
+
+  switch (aInputEvent.mClass) {
+    case eMouseEventClass:
+    case eMouseScrollEventClass:
+    case eWheelEventClass:
+    case eDragEventClass:
+    case eSimpleGestureEventClass:
+      InitMouseEvent(aInputEvent);
+      break;
+    default:
+      break;
+  }
+}
+
+void ModifierKeyState::InitMouseEvent(WidgetInputEvent& aMouseEvent) const {
+  NS_ASSERTION(aMouseEvent.mClass == eMouseEventClass ||
+                   aMouseEvent.mClass == eWheelEventClass ||
+                   aMouseEvent.mClass == eDragEventClass ||
+                   aMouseEvent.mClass == eSimpleGestureEventClass,
+               "called with non-mouse event");
+
+  WidgetMouseEventBase& mouseEvent = *aMouseEvent.AsMouseEventBase();
+  mouseEvent.mButtons = 0;
+  if (::GetKeyState(VK_LBUTTON) < 0) {
+    mouseEvent.mButtons |= MouseButtonsFlag::ePrimaryFlag;
+  }
+  if (::GetKeyState(VK_RBUTTON) < 0) {
+    mouseEvent.mButtons |= MouseButtonsFlag::eSecondaryFlag;
+  }
+  if (::GetKeyState(VK_MBUTTON) < 0) {
+    mouseEvent.mButtons |= MouseButtonsFlag::eMiddleFlag;
+  }
+  if (::GetKeyState(VK_XBUTTON1) < 0) {
+    mouseEvent.mButtons |= MouseButtonsFlag::e4thFlag;
+  }
+  if (::GetKeyState(VK_XBUTTON2) < 0) {
+    mouseEvent.mButtons |= MouseButtonsFlag::e5thFlag;
+  }
+}
+
+bool ModifierKeyState::IsShift() const {
+  return (mModifiers & MODIFIER_SHIFT) != 0;
+}
+
+bool ModifierKeyState::IsControl() const {
+  return (mModifiers & MODIFIER_CONTROL) != 0;
+}
+
+bool ModifierKeyState::IsAlt() const {
+  return (mModifiers & MODIFIER_ALT) != 0;
+}
+
+bool ModifierKeyState::IsWin() const {
+  return (mModifiers & MODIFIER_META) != 0;
+}
+
+bool ModifierKeyState::MaybeMatchShortcutKey() const {
+  // If Windows key is pressed, even if both Ctrl key and Alt key are pressed,
+  // it's possible to match a shortcut key.
+  if (IsWin()) {
+    return true;
+  }
+  // Otherwise, when both Ctrl key and Alt key are pressed, it shouldn't be
+  // a shortcut key for Windows since it means pressing AltGr key on
+  // some keyboard layouts.
+  if (IsControl() ^ IsAlt()) {
+    return true;
+  }
+  // If no modifier key is active except a lockable modifier nor Shift key,
+  // the key shouldn't match any shortcut keys (there are Space and
+  // Shift+Space, though, let's ignore these special case...).
+  return false;
+}
+
+bool ModifierKeyState::IsCapsLocked() const {
+  return (mModifiers & MODIFIER_CAPSLOCK) != 0;
+}
+
+bool ModifierKeyState::IsNumLocked() const {
+  return (mModifiers & MODIFIER_NUMLOCK) != 0;
+}
+
+bool ModifierKeyState::IsScrollLocked() const {
+  return (mModifiers & MODIFIER_SCROLLLOCK) != 0;
+}
+
+/*****************************************************************************
+ * mozilla::widget::UniCharsAndModifiers
+ *****************************************************************************/
+
+void UniCharsAndModifiers::Append(char16_t aUniChar, Modifiers aModifiers) {
+  mChars.Append(aUniChar);
+  mModifiers.AppendElement(aModifiers);
+}
+
+void UniCharsAndModifiers::FillModifiers(Modifiers aModifiers) {
+  for (size_t i = 0; i < Length(); i++) {
+    mModifiers[i] = aModifiers;
+  }
+}
+
+void UniCharsAndModifiers::OverwriteModifiersIfBeginsWith(
+    const UniCharsAndModifiers& aOther) {
+  if (!BeginsWith(aOther)) {
+    return;
+  }
+  for (size_t i = 0; i < aOther.Length(); ++i) {
+    mModifiers[i] = aOther.mModifiers[i];
+  }
+}
+
+bool UniCharsAndModifiers::UniCharsEqual(
+    const UniCharsAndModifiers& aOther) const {
+  return mChars.Equals(aOther.mChars);
+}
+
+bool UniCharsAndModifiers::UniCharsCaseInsensitiveEqual(
+    const UniCharsAndModifiers& aOther) const {
+  return mChars.Equals(aOther.mChars, nsCaseInsensitiveStringComparator);
+}
+
+bool UniCharsAndModifiers::BeginsWith(
+    const UniCharsAndModifiers& aOther) const {
+  return StringBeginsWith(mChars, aOther.mChars);
+}
+
+UniCharsAndModifiers& UniCharsAndModifiers::operator+=(
+    const UniCharsAndModifiers& aOther) {
+  mChars.Append(aOther.mChars);
+  mModifiers.AppendElements(aOther.mModifiers);
+  return *this;
+}
+
+UniCharsAndModifiers UniCharsAndModifiers::operator+(
+    const UniCharsAndModifiers& aOther) const {
+  UniCharsAndModifiers result(*this);
+  result += aOther;
+  return result;
+}
+
+/*****************************************************************************
+ * mozilla::widget::VirtualKey
+ *****************************************************************************/
+
+// static
+VirtualKey::ShiftState VirtualKey::ModifiersToShiftState(Modifiers aModifiers) {
+  ShiftState state = 0;
+  if (aModifiers & MODIFIER_SHIFT) {
+    state |= STATE_SHIFT;
+  }
+  if (aModifiers & MODIFIER_ALTGRAPH) {
+    state |= STATE_ALTGRAPH;
+  } else {
+    if (aModifiers & MODIFIER_CONTROL) {
+      state |= STATE_CONTROL;
+    }
+    if (aModifiers & MODIFIER_ALT) {
+      state |= STATE_ALT;
+    }
+  }
+  if (aModifiers & MODIFIER_CAPSLOCK) {
+    state |= STATE_CAPSLOCK;
+  }
+  return state;
+}
+
+// static
+Modifiers VirtualKey::ShiftStateToModifiers(ShiftState aShiftState) {
+  Modifiers modifiers = 0;
+  if (aShiftState & STATE_SHIFT) {
+    modifiers |= MODIFIER_SHIFT;
+  }
+  if (aShiftState & STATE_ALTGRAPH) {
+    modifiers |= MODIFIER_ALTGRAPH;
+  } else {
+    if (aShiftState & STATE_CONTROL) {
+      modifiers |= MODIFIER_CONTROL;
+    }
+    if (aShiftState & STATE_ALT) {
+      modifiers |= MODIFIER_ALT;
+    }
+  }
+  if (aShiftState & STATE_CAPSLOCK) {
+    modifiers |= MODIFIER_CAPSLOCK;
+  }
+  return modifiers;
+}
+
+const DeadKeyTable* VirtualKey::MatchingDeadKeyTable(
+    const DeadKeyEntry* aDeadKeyArray, uint32_t aEntries) const {
+  if (!mIsDeadKey) {
+    return nullptr;
+  }
+
+  for (ShiftState shiftState = 0; shiftState < 16; shiftState++) {
+    if (!IsDeadKey(shiftState)) {
+      continue;
+    }
+    const DeadKeyTable* dkt = mShiftStates[shiftState].DeadKey.Table;
+    if (dkt && dkt->IsEqual(aDeadKeyArray, aEntries)) {
+      return dkt;
+    }
+  }
+
+  return nullptr;
+}
+
+void VirtualKey::SetNormalChars(ShiftState aShiftState, const char16_t* aChars,
+                                uint32_t aNumOfChars) {
+  MOZ_ASSERT(aShiftState == ToShiftStateIndex(aShiftState));
+
+  SetDeadKey(aShiftState, false);
+
+  for (uint32_t index = 0; index < aNumOfChars; index++) {
+    // Ignore legacy non-printable control characters
+    mShiftStates[aShiftState].Normal.Chars[index] =
+        (aChars[index] >= 0x20) ? aChars[index] : 0;
+  }
+
+  uint32_t len = ArrayLength(mShiftStates[aShiftState].Normal.Chars);
+  for (uint32_t index = aNumOfChars; index < len; index++) {
+    mShiftStates[aShiftState].Normal.Chars[index] = 0;
+  }
+}
+
+void VirtualKey::SetDeadChar(ShiftState aShiftState, char16_t aDeadChar) {
+  MOZ_ASSERT(aShiftState == ToShiftStateIndex(aShiftState));
+
+  SetDeadKey(aShiftState, true);
+
+  mShiftStates[aShiftState].DeadKey.DeadChar = aDeadChar;
+  mShiftStates[aShiftState].DeadKey.Table = nullptr;
+}
+
+UniCharsAndModifiers VirtualKey::GetUniChars(ShiftState aShiftState) const {
+  UniCharsAndModifiers result = GetNativeUniChars(aShiftState);
+
+  const uint8_t kShiftStateIndex = ToShiftStateIndex(aShiftState);
+  if (!(kShiftStateIndex & STATE_CONTROL_ALT)) {
+    // If neither Alt nor Ctrl key is pressed, just return stored data
+    // for the key.
+    return result;
+  }
+
+  if (result.IsEmpty()) {
+    // If Alt and/or Control are pressed and the key produces no
+    // character, return characters which is produced by the key without
+    // Alt and Control, and return given modifiers as is.
+    result = GetNativeUniChars(kShiftStateIndex & ~STATE_CONTROL_ALT);
+    result.FillModifiers(ShiftStateToModifiers(aShiftState));
+    return result;
+  }
+
+  if (IsAltGrIndex(kShiftStateIndex)) {
+    // If AltGr or both Ctrl and Alt are pressed and the key produces
+    // character(s), we need to clear MODIFIER_ALT and MODIFIER_CONTROL
+    // since TextEditor won't handle eKeyPress event whose mModifiers
+    // has MODIFIER_ALT or MODIFIER_CONTROL.  Additionally, we need to
+    // use MODIFIER_ALTGRAPH when a key produces character(s) with
+    // AltGr or both Ctrl and Alt on Windows.  See following spec issue:
+    // <https://github.com/w3c/uievents/issues/147>
+    Modifiers finalModifiers = ShiftStateToModifiers(aShiftState);
+    finalModifiers &= ~(MODIFIER_ALT | MODIFIER_CONTROL);
+    finalModifiers |= MODIFIER_ALTGRAPH;
+    result.FillModifiers(finalModifiers);
+    return result;
+  }
+
+  // Otherwise, i.e., Alt or Ctrl is pressed and it produces character(s),
+  // check if different character(s) is produced by the key without Alt/Ctrl.
+  // If it produces different character, we need to consume the Alt and
+  // Ctrl modifier for TextEditor.  Otherwise, the key does not produces the
+  // character actually.  So, keep setting Alt and Ctrl modifiers.
+  UniCharsAndModifiers unmodifiedReslt =
+      GetNativeUniChars(kShiftStateIndex & ~STATE_CONTROL_ALT);
+  if (!result.UniCharsEqual(unmodifiedReslt)) {
+    Modifiers finalModifiers = ShiftStateToModifiers(aShiftState);
+    finalModifiers &= ~(MODIFIER_ALT | MODIFIER_CONTROL);
+    result.FillModifiers(finalModifiers);
+  }
+  return result;
+}
+
+UniCharsAndModifiers VirtualKey::GetNativeUniChars(
+    ShiftState aShiftState) const {
+  const uint8_t kShiftStateIndex = ToShiftStateIndex(aShiftState);
+  UniCharsAndModifiers result;
+  Modifiers modifiers = ShiftStateToModifiers(aShiftState);
+  if (IsDeadKey(aShiftState)) {
+    result.Append(mShiftStates[kShiftStateIndex].DeadKey.DeadChar, modifiers);
+    return result;
+  }
+
+  uint32_t len = ArrayLength(mShiftStates[kShiftStateIndex].Normal.Chars);
+  for (uint32_t i = 0;
+       i < len && mShiftStates[kShiftStateIndex].Normal.Chars[i]; i++) {
+    result.Append(mShiftStates[kShiftStateIndex].Normal.Chars[i], modifiers);
+  }
+  return result;
+}
+
+// static
+void VirtualKey::FillKbdState(PBYTE aKbdState, const ShiftState aShiftState) {
+  if (aShiftState & STATE_SHIFT) {
+    aKbdState[VK_SHIFT] |= 0x80;
+  } else {
+    aKbdState[VK_SHIFT] &= ~0x80;
+    aKbdState[VK_LSHIFT] &= ~0x80;
+    aKbdState[VK_RSHIFT] &= ~0x80;
+  }
+
+  if (aShiftState & STATE_ALTGRAPH) {
+    aKbdState[VK_CONTROL] |= 0x80;
+    aKbdState[VK_LCONTROL] |= 0x80;
+    aKbdState[VK_RCONTROL] &= ~0x80;
+    aKbdState[VK_MENU] |= 0x80;
+    aKbdState[VK_LMENU] &= ~0x80;
+    aKbdState[VK_RMENU] |= 0x80;
+  } else {
+    if (aShiftState & STATE_CONTROL) {
+      aKbdState[VK_CONTROL] |= 0x80;
+    } else {
+      aKbdState[VK_CONTROL] &= ~0x80;
+      aKbdState[VK_LCONTROL] &= ~0x80;
+      aKbdState[VK_RCONTROL] &= ~0x80;
+    }
+
+    if (aShiftState & STATE_ALT) {
+      aKbdState[VK_MENU] |= 0x80;
+    } else {
+      aKbdState[VK_MENU] &= ~0x80;
+      aKbdState[VK_LMENU] &= ~0x80;
+      aKbdState[VK_RMENU] &= ~0x80;
+    }
+  }
+
+  if (aShiftState & STATE_CAPSLOCK) {
+    aKbdState[VK_CAPITAL] |= 0x01;
+  } else {
+    aKbdState[VK_CAPITAL] &= ~0x01;
+  }
+}
+
+/*****************************************************************************
+ * mozilla::widget::NativeKey
+ *****************************************************************************/
+
+uint8_t NativeKey::sDispatchedKeyOfAppCommand = 0;
+NativeKey* NativeKey::sLatestInstance = nullptr;
+const MSG NativeKey::sEmptyMSG = {};
+MSG NativeKey::sLastKeyOrCharMSG = {};
+MSG NativeKey::sLastKeyMSG = {};
+char16_t NativeKey::sPendingHighSurrogate = 0;
+
+NativeKey::NativeKey(nsWindow* aWidget, const MSG& aMessage,
+                     const ModifierKeyState& aModKeyState,
+                     HKL aOverrideKeyboardLayout,
+                     nsTArray<FakeCharMsg>* aFakeCharMsgs)
+    : mLastInstance(sLatestInstance),
+      mRemovingMsg(sEmptyMSG),
+      mReceivedMsg(sEmptyMSG),
+      mWidget(aWidget),
+      mDispatcher(aWidget->GetTextEventDispatcher()),
+      mMsg(aMessage),
+      mFocusedWndBeforeDispatch(::GetFocus()),
+      mDOMKeyCode(0),
+      mKeyNameIndex(KEY_NAME_INDEX_Unidentified),
+      mCodeNameIndex(CODE_NAME_INDEX_UNKNOWN),
+      mModKeyState(aModKeyState),
+      mVirtualKeyCode(0),
+      mOriginalVirtualKeyCode(0),
+      mShiftedLatinChar(0),
+      mUnshiftedLatinChar(0),
+      mScanCode(0),
+      mIsExtended(false),
+      mIsRepeat(false),
+      mIsDeadKey(false),
+      mIsPrintableKey(false),
+      mIsSkippableInRemoteProcess(false),
+      mCharMessageHasGone(false),
+      mCanIgnoreModifierStateAtKeyPress(true),
+      mFakeCharMsgs(aFakeCharMsgs && aFakeCharMsgs->Length() ? aFakeCharMsgs
+                                                             : nullptr) {
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p NativeKey::NativeKey(aWidget=0x%p { GetWindowHandle()=0x%p }, "
+           "aMessage=%s, aModKeyState=%s), sLatestInstance=0x%p",
+           this, aWidget, aWidget->GetWindowHandle(), ToString(aMessage).get(),
+           ToString(aModKeyState).get(), sLatestInstance));
+
+  MOZ_ASSERT(aWidget);
+  MOZ_ASSERT(mDispatcher);
+  sLatestInstance = this;
+  KeyboardLayout* keyboardLayout = KeyboardLayout::GetInstance();
+  mKeyboardLayout = KeyboardLayout::GetLayout();
+  if (aOverrideKeyboardLayout && mKeyboardLayout != aOverrideKeyboardLayout) {
+    keyboardLayout->OverrideLayout(aOverrideKeyboardLayout);
+    mKeyboardLayout = keyboardLayout->GetLoadedLayout();
+    MOZ_ASSERT(mKeyboardLayout == aOverrideKeyboardLayout);
+    mIsOverridingKeyboardLayout = true;
+  } else {
+    mIsOverridingKeyboardLayout = false;
+    sLastKeyOrCharMSG = aMessage;
+  }
+
+  if (mMsg.message == WM_APPCOMMAND) {
+    InitWithAppCommand();
+  } else {
+    InitWithKeyOrChar();
+  }
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::NativeKey(), mKeyboardLayout=0x%p, "
+           "mFocusedWndBeforeDispatch=0x%p, mDOMKeyCode=%s, "
+           "mKeyNameIndex=%s, mCodeNameIndex=%s, mModKeyState=%s, "
+           "mVirtualKeyCode=%s, mOriginalVirtualKeyCode=%s, "
+           "mCommittedCharsAndModifiers=%s, mInputtingStringAndModifiers=%s, "
+           "mShiftedString=%s, mUnshiftedString=%s, mShiftedLatinChar=%s, "
+           "mUnshiftedLatinChar=%s, mScanCode=0x%04X, mIsExtended=%s, "
+           "mIsRepeat=%s, mIsDeadKey=%s, mIsPrintableKey=%s, "
+           "mIsSkippableInRemoteProcess=%s, mCharMessageHasGone=%s, "
+           "mIsOverridingKeyboardLayout=%s",
+           this, mKeyboardLayout, mFocusedWndBeforeDispatch,
+           GetDOMKeyCodeName(mDOMKeyCode).get(), ToString(mKeyNameIndex).get(),
+           ToString(mCodeNameIndex).get(), ToString(mModKeyState).get(),
+           GetVirtualKeyCodeName(mVirtualKeyCode).get(),
+           GetVirtualKeyCodeName(mOriginalVirtualKeyCode).get(),
+           ToString(mCommittedCharsAndModifiers).get(),
+           ToString(mInputtingStringAndModifiers).get(),
+           ToString(mShiftedString).get(), ToString(mUnshiftedString).get(),
+           GetCharacterCodeName(mShiftedLatinChar).get(),
+           GetCharacterCodeName(mUnshiftedLatinChar).get(), mScanCode,
+           GetBoolName(mIsExtended), GetBoolName(mIsRepeat),
+           GetBoolName(mIsDeadKey), GetBoolName(mIsPrintableKey),
+           GetBoolName(mIsSkippableInRemoteProcess),
+           GetBoolName(mCharMessageHasGone),
+           GetBoolName(mIsOverridingKeyboardLayout)));
+}
+
+void NativeKey::InitIsSkippableForKeyOrChar(const MSG& aLastKeyMSG) {
+  mIsSkippableInRemoteProcess = false;
+
+  if (!mIsRepeat) {
+    // If the message is not repeated key message, the event should be always
+    // handled in remote process even if it's too old.
+    return;
+  }
+
+  // Keyboard utilities may send us some generated messages and such messages
+  // may be marked as "repeated", e.g., SendInput() calls with
+  // KEYEVENTF_UNICODE but without KEYEVENTF_KEYUP.   However, key sequence
+  // comes from such utilities may be really important.  For example, utilities
+  // may send WM_KEYDOWN for VK_BACK to remove previous character and send
+  // WM_KEYDOWN for VK_PACKET to insert a composite character.  Therefore, we
+  // should check if current message and previous key message are caused by
+  // same physical key.  If not, the message may be generated by such
+  // utility.
+  // XXX With this approach, if VK_BACK messages are generated with known
+  //     scancode, we cannot distinguish whether coming VK_BACK message is
+  //     actually repeated by the auto-repeat feature.  Currently, we need
+  //     this hack only for "SinhalaTamil IME" and fortunately, it generates
+  //     VK_BACK messages with odd scancode.  So, we don't need to handle
+  //     VK_BACK specially at least for now.
+
+  if (mCodeNameIndex == CODE_NAME_INDEX_UNKNOWN) {
+    // If current event is not caused by physical key operation, it may be
+    // caused by a keyboard utility.  If so, the event shouldn't be ignored by
+    // BrowserChild since it want to insert the character, delete a character or
+    // move caret.
+    return;
+  }
+
+  if (mOriginalVirtualKeyCode == VK_PACKET) {
+    // If the message is VK_PACKET, that means that a keyboard utility
+    // tries to insert a character.
+    return;
+  }
+
+  switch (mMsg.message) {
+    case WM_KEYDOWN:
+    case WM_SYSKEYDOWN:
+    case WM_CHAR:
+    case WM_SYSCHAR:
+    case WM_DEADCHAR:
+    case WM_SYSDEADCHAR:
+      // However, some keyboard layouts may send some keyboard messages with
+      // activating the bit.  If we dispatch repeated keyboard events, they
+      // may be ignored by BrowserChild due to performance reason.  So, we need
+      // to check if actually a physical key is repeated by the auto-repeat
+      // feature.
+      switch (aLastKeyMSG.message) {
+        case WM_KEYDOWN:
+        case WM_SYSKEYDOWN:
+          if (aLastKeyMSG.wParam == VK_PACKET) {
+            // If the last message was VK_PACKET, that means that a keyboard
+            // utility tried to insert a character.  So, current message is
+            // not repeated key event of the previous event.
+            return;
+          }
+          // Let's check whether current message and previous message are
+          // caused by same physical key.
+          mIsSkippableInRemoteProcess =
+              mScanCode == WinUtils::GetScanCode(aLastKeyMSG.lParam) &&
+              mIsExtended == WinUtils::IsExtendedScanCode(aLastKeyMSG.lParam);
+          return;
+        default:
+          // If previous message is not a keydown, this must not be generated
+          // by the auto-repeat feature.
+          return;
+      }
+    case WM_APPCOMMAND:
+      MOZ_ASSERT_UNREACHABLE(
+          "WM_APPCOMMAND should be handled in "
+          "InitWithAppCommand()");
+      return;
+    default:
+      // keyup message shouldn't be repeated by the auto-repeat feature.
+      return;
+  }
+}
+
+void NativeKey::InitWithKeyOrChar() {
+  MSG lastKeyMSG = sLastKeyMSG;
+  char16_t pendingHighSurrogate = sPendingHighSurrogate;
+  mScanCode = WinUtils::GetScanCode(mMsg.lParam);
+  mIsExtended = WinUtils::IsExtendedScanCode(mMsg.lParam);
+  switch (mMsg.message) {
+    case WM_KEYDOWN:
+    case WM_SYSKEYDOWN:
+      sPendingHighSurrogate = 0;
+      [[fallthrough]];
+    case WM_KEYUP:
+    case WM_SYSKEYUP: {
+      // Modify sLastKeyMSG now since retrieving following char messages may
+      // cause sending another key message if odd tool hooks GetMessage(),
+      // PeekMessage().
+      sLastKeyMSG = mMsg;
+
+      // Note that we don't need to compute raw virtual keycode here even when
+      // it's VK_PROCESS (i.e., already handled by IME) because we need to
+      // export it as DOM_VK_PROCESS and KEY_NAME_INDEX_Process.
+      mOriginalVirtualKeyCode = static_cast<uint8_t>(mMsg.wParam);
+
+      // If the key message is sent from other application like a11y tools, the
+      // scancode value might not be set proper value.  Then, probably the value
+      // is 0.
+      // NOTE: If the virtual keycode can be caused by both non-extended key
+      //       and extended key, the API returns the non-extended key's
+      //       scancode.  E.g., VK_LEFT causes "4" key on numpad.
+      if (!mScanCode && mOriginalVirtualKeyCode != VK_PACKET) {
+        uint16_t scanCodeEx = ComputeScanCodeExFromVirtualKeyCode(mMsg.wParam);
+        if (scanCodeEx) {
+          mScanCode = static_cast<uint8_t>(scanCodeEx & 0xFF);
+          uint8_t extended = static_cast<uint8_t>((scanCodeEx & 0xFF00) >> 8);
+          mIsExtended = (extended == 0xE0) || (extended == 0xE1);
+        }
+      }
+
+      // Most keys are not distinguished as left or right keys.
+      bool isLeftRightDistinguishedKey = false;
+
+      // mOriginalVirtualKeyCode must not distinguish left or right of
+      // Shift, Control or Alt.
+      switch (mOriginalVirtualKeyCode) {
+        case VK_SHIFT:
+        case VK_CONTROL:
+        case VK_MENU:
+          isLeftRightDistinguishedKey = true;
+          break;
+        case VK_LSHIFT:
+        case VK_RSHIFT:
+          mVirtualKeyCode = mOriginalVirtualKeyCode;
+          mOriginalVirtualKeyCode = VK_SHIFT;
+          isLeftRightDistinguishedKey = true;
+          break;
+        case VK_LCONTROL:
+        case VK_RCONTROL:
+          mVirtualKeyCode = mOriginalVirtualKeyCode;
+          mOriginalVirtualKeyCode = VK_CONTROL;
+          isLeftRightDistinguishedKey = true;
+          break;
+        case VK_LMENU:
+        case VK_RMENU:
+          mVirtualKeyCode = mOriginalVirtualKeyCode;
+          mOriginalVirtualKeyCode = VK_MENU;
+          isLeftRightDistinguishedKey = true;
+          break;
+      }
+
+      // If virtual keycode (left-right distinguished keycode) is already
+      // computed, we don't need to do anymore.
+      if (mVirtualKeyCode) {
+        break;
+      }
+
+      // If the keycode doesn't have LR distinguished keycode, we just set
+      // mOriginalVirtualKeyCode to mVirtualKeyCode.  Note that don't compute
+      // it from MapVirtualKeyEx() because the scan code might be wrong if
+      // the message is sent/posted by other application.  Then, we will compute
+      // unexpected keycode from the scan code.
+      if (!isLeftRightDistinguishedKey) {
+        break;
+      }
+
+      NS_ASSERTION(!mVirtualKeyCode,
+                   "mVirtualKeyCode has been computed already");
+
+      // Otherwise, compute the virtual keycode with MapVirtualKeyEx().
+      mVirtualKeyCode = ComputeVirtualKeyCodeFromScanCodeEx();
+
+      // Following code shouldn't be used now because we compute scancode value
+      // if we detect that the sender doesn't set proper scancode.
+      // However, the detection might fail. Therefore, let's keep using this.
+      switch (mOriginalVirtualKeyCode) {
+        case VK_CONTROL:
+          if (mVirtualKeyCode != VK_LCONTROL &&
+              mVirtualKeyCode != VK_RCONTROL) {
+            mVirtualKeyCode = mIsExtended ? VK_RCONTROL : VK_LCONTROL;
+          }
+          break;
+        case VK_MENU:
+          if (mVirtualKeyCode != VK_LMENU && mVirtualKeyCode != VK_RMENU) {
+            mVirtualKeyCode = mIsExtended ? VK_RMENU : VK_LMENU;
+          }
+          break;
+        case VK_SHIFT:
+          if (mVirtualKeyCode != VK_LSHIFT && mVirtualKeyCode != VK_RSHIFT) {
+            // Neither left shift nor right shift is an extended key,
+            // let's use VK_LSHIFT for unknown mapping.
+            mVirtualKeyCode = VK_LSHIFT;
+          }
+          break;
+        default:
+          MOZ_CRASH("Unsupported mOriginalVirtualKeyCode");
+      }
+      break;
+    }
+    case WM_CHAR:
+    case WM_UNICHAR:
+    case WM_SYSCHAR:
+      sPendingHighSurrogate = 0;
+      // If there is another instance and it is trying to remove a char message
+      // from the queue, this message should be handled in the old instance.
+      if (IsAnotherInstanceRemovingCharMessage()) {
+        // XXX Do we need to make mReceivedMsg an array?
+        MOZ_ASSERT(IsEmptyMSG(mLastInstance->mReceivedMsg));
+        MOZ_LOG(
+            gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::InitWithKeyOrChar(), WARNING, detecting another "
+             "instance is trying to remove a char message, so, this instance "
+             "should do nothing, mLastInstance=0x%p, mRemovingMsg=%s, "
+             "mReceivedMsg=%s",
+             this, mLastInstance, ToString(mLastInstance->mRemovingMsg).get(),
+             ToString(mLastInstance->mReceivedMsg).get()));
+        mLastInstance->mReceivedMsg = mMsg;
+        return;
+      }
+
+      // NOTE: If other applications like a11y tools sends WM_*CHAR without
+      //       scancode, we cannot compute virtual keycode.  I.e., with such
+      //       applications, we cannot generate proper KeyboardEvent.code value.
+
+      mVirtualKeyCode = mOriginalVirtualKeyCode =
+          ComputeVirtualKeyCodeFromScanCodeEx();
+      NS_ASSERTION(mVirtualKeyCode, "Failed to compute virtual keycode");
+      break;
+    default: {
+      MOZ_CRASH_UNSAFE_PRINTF("Unsupported message: 0x%04X", mMsg.message);
+      break;
+    }
+  }
+
+  if (!mVirtualKeyCode) {
+    mVirtualKeyCode = mOriginalVirtualKeyCode;
+  }
+
+  KeyboardLayout* keyboardLayout = KeyboardLayout::GetInstance();
+  mDOMKeyCode =
+      keyboardLayout->ConvertNativeKeyCodeToDOMKeyCode(mVirtualKeyCode);
+  // Be aware, keyboard utilities can change non-printable keys to printable
+  // keys.  In such case, we should make the key value as a printable key.
+  // FYI: IsFollowedByPrintableCharMessage() returns true only when it's
+  //      handling a keydown message.
+  mKeyNameIndex =
+      IsFollowedByPrintableCharMessage()
+          ? KEY_NAME_INDEX_USE_STRING
+          : keyboardLayout->ConvertNativeKeyCodeToKeyNameIndex(mVirtualKeyCode);
+  mCodeNameIndex = KeyboardLayout::ConvertScanCodeToCodeNameIndex(
+      GetScanCodeWithExtendedFlag());
+
+  // If next message of WM_(SYS)KEYDOWN is WM_*CHAR message and the key
+  // combination is not reserved by the system, let's consume it now.
+  // TODO: We cannot initialize mCommittedCharsAndModifiers for VK_PACKET
+  //       if the message is WM_KEYUP because we don't have preceding
+  //       WM_CHAR message.
+  // TODO: Like Edge, we shouldn't dispatch two sets of keyboard events
+  //       for a Unicode character in non-BMP because its key value looks
+  //       broken and not good thing for our editor if only one keydown or
+  //       keypress event's default is prevented.  I guess, we should store
+  //       key message information globally and we should wait following
+  //       WM_KEYDOWN if following WM_CHAR is a part of a Unicode character.
+  if ((mMsg.message == WM_KEYDOWN || mMsg.message == WM_SYSKEYDOWN) &&
+      !IsReservedBySystem()) {
+    MSG charMsg;
+    while (GetFollowingCharMessage(charMsg)) {
+      // Although, got message shouldn't be WM_NULL in desktop apps,
+      // we should keep checking this.  FYI: This was added for Metrofox.
+      if (charMsg.message == WM_NULL) {
+        continue;
+      }
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("%p   NativeKey::InitWithKeyOrChar(), removed char message, %s",
+               this, ToString(charMsg).get()));
+      Unused << NS_WARN_IF(charMsg.hwnd != mMsg.hwnd);
+      mFollowingCharMsgs.AppendElement(charMsg);
+    }
+    if (mFollowingCharMsgs.Length() == 1) {
+      // If we receive a keydown message for a high-surrogate, a low-surrogate
+      // keydown message **will** and should follow it.  We cannot translate the
+      // following WM_KEYDOWN message for the low-surrogate right now since
+      // it's not yet queued into the message queue yet.  Therefore, we need to
+      // wait next one to dispatch keypress event with setting its `.key` value
+      // to a surrogate pair rather than setting it to a lone surrogate.
+      // FYI: This may happen with typing a non-BMP character on the touch
+      // keyboard on Windows 10 or later except when an IME is installed. (If
+      // IME is installed, composition is used instead.)
+      if (IS_HIGH_SURROGATE(mFollowingCharMsgs[0].wParam)) {
+        if (pendingHighSurrogate) {
+          MOZ_LOG(gKeyLog, LogLevel::Warning,
+                  ("%p   NativeKey::InitWithKeyOrChar(), there is pending "
+                   "high surrogate input, but received another high surrogate "
+                   "input.  The previous one is discarded",
+                   this));
+        }
+        sPendingHighSurrogate = mFollowingCharMsgs[0].wParam;
+        mFollowingCharMsgs.Clear();
+      } else if (IS_LOW_SURROGATE(mFollowingCharMsgs[0].wParam)) {
+        // If we stopped dispathing a keypress event for a preceding
+        // high-surrogate, treat this keydown (for a low-surrogate) as
+        // introducing both the high surrogate and the low surrogate.
+        if (pendingHighSurrogate) {
+          MSG charMsg = mFollowingCharMsgs[0];
+          mFollowingCharMsgs[0].wParam = pendingHighSurrogate;
+          mFollowingCharMsgs.AppendElement(std::move(charMsg));
+        } else {
+          MOZ_LOG(
+              gKeyLog, LogLevel::Warning,
+              ("%p   NativeKey::InitWithKeyOrChar(), there is no pending high "
+               "surrogate input, but received lone low surrogate input",
+               this));
+        }
+      } else {
+        MOZ_LOG(gKeyLog, LogLevel::Warning,
+                ("%p   NativeKey::InitWithKeyOrChar(), there is pending "
+                 "high surrogate input, but received non-surrogate input.  "
+                 "The high surrogate input is discarded",
+                 this));
+      }
+    } else if (!mFollowingCharMsgs.IsEmpty()) {
+      MOZ_LOG(gKeyLog, LogLevel::Warning,
+              ("%p   NativeKey::InitWithKeyOrChar(), there is pending "
+               "high surrogate input, but received 2 or more character input.  "
+               "The high surrogate input is discarded",
+               this));
+    }
+  }
+
+  keyboardLayout->InitNativeKey(*this);
+
+  // Now, we can know if the key produces character(s) or a dead key with
+  // AltGraph modifier.  When user emulates AltGr key press with pressing
+  // both Ctrl and Alt and the key produces character(s) or a dead key, we
+  // need to replace Control and Alt state with AltGraph if the keyboard
+  // layout has AltGr key.
+  // Note that if Ctrl and/or Alt are pressed (not to emulate to press AltGr),
+  // we need to set actual modifiers to eKeyDown and eKeyUp.
+  if (MaybeEmulatingAltGraph() &&
+      (mCommittedCharsAndModifiers.IsProducingCharsWithAltGr() ||
+       mKeyNameIndex == KEY_NAME_INDEX_Dead)) {
+    mModKeyState.Unset(MODIFIER_CONTROL | MODIFIER_ALT);
+    mModKeyState.Set(MODIFIER_ALTGRAPH);
+  }
+
+  mIsDeadKey =
+      (IsFollowedByDeadCharMessage() ||
+       keyboardLayout->IsDeadKey(mOriginalVirtualKeyCode, mModKeyState));
+  mIsPrintableKey = mKeyNameIndex == KEY_NAME_INDEX_USE_STRING ||
+                    KeyboardLayout::IsPrintableCharKey(mOriginalVirtualKeyCode);
+  // The repeat count in mMsg.lParam isn't useful to check whether the event
+  // is caused by the auto-repeat feature because it's not incremented even
+  // if it's repeated twice or more (i.e., always 1).  Therefore, we need to
+  // check previous key state (31th bit) instead.  If it's 1, the key was down
+  // before the message was sent.
+  mIsRepeat = (mMsg.lParam & (1 << 30)) != 0;
+  InitIsSkippableForKeyOrChar(lastKeyMSG);
+
+  if (IsKeyDownMessage()) {
+    // Compute some strings which may be inputted by the key with various
+    // modifier state if this key event won't cause text input actually.
+    // They will be used for setting mAlternativeCharCodes in the callback
+    // method which will be called by TextEventDispatcher.
+    if (!IsFollowedByPrintableCharMessage()) {
+      ComputeInputtingStringWithKeyboardLayout();
+    }
+    // Remove odd char messages if there are.
+    RemoveFollowingOddCharMessages();
+  }
+}
+
+void NativeKey::InitCommittedCharsAndModifiersWithFollowingCharMessages() {
+  mCommittedCharsAndModifiers.Clear();
+  // This should cause inputting text in focused editor.  However, it
+  // ignores keypress events whose altKey or ctrlKey is true.
+  // Therefore, we need to remove these modifier state here.
+  Modifiers modifiers = mModKeyState.GetModifiers();
+  if (IsFollowedByPrintableCharMessage()) {
+    modifiers &= ~(MODIFIER_ALT | MODIFIER_CONTROL);
+    if (MaybeEmulatingAltGraph()) {
+      modifiers |= MODIFIER_ALTGRAPH;
+    }
+  }
+  // NOTE: This method assumes that WM_CHAR and WM_SYSCHAR are never retrieved
+  //       at same time.
+  for (size_t i = 0; i < mFollowingCharMsgs.Length(); ++i) {
+    // Ignore non-printable char messages.
+    if (!IsPrintableCharOrSysCharMessage(mFollowingCharMsgs[i])) {
+      continue;
+    }
+    char16_t ch = static_cast<char16_t>(mFollowingCharMsgs[i].wParam);
+    mCommittedCharsAndModifiers.Append(ch, modifiers);
+  }
+}
+
+NativeKey::~NativeKey() {
+  MOZ_LOG(gKeyLog, LogLevel::Debug,
+          ("%p   NativeKey::~NativeKey(), destroyed", this));
+  if (mIsOverridingKeyboardLayout) {
+    KeyboardLayout* keyboardLayout = KeyboardLayout::GetInstance();
+    keyboardLayout->RestoreLayout();
+  }
+  sLatestInstance = mLastInstance;
+}
+
+void NativeKey::InitWithAppCommand() {
+  if (GET_DEVICE_LPARAM(mMsg.lParam) != FAPPCOMMAND_KEY) {
+    return;
+  }
+
+  uint32_t appCommand = GET_APPCOMMAND_LPARAM(mMsg.lParam);
+  switch (GET_APPCOMMAND_LPARAM(mMsg.lParam)) {
+#undef NS_APPCOMMAND_TO_DOM_KEY_NAME_INDEX
+#define NS_APPCOMMAND_TO_DOM_KEY_NAME_INDEX(aAppCommand, aKeyNameIndex) \
+  case aAppCommand:                                                     \
+    mKeyNameIndex = aKeyNameIndex;                                      \
+    break;
+
+#include "NativeKeyToDOMKeyName.h"
+
+#undef NS_APPCOMMAND_TO_DOM_KEY_NAME_INDEX
+
+    default:
+      mKeyNameIndex = KEY_NAME_INDEX_Unidentified;
+  }
+
+  // Guess the virtual keycode which caused this message.
+  switch (appCommand) {
+    case APPCOMMAND_BROWSER_BACKWARD:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_BROWSER_BACK;
+      break;
+    case APPCOMMAND_BROWSER_FORWARD:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_BROWSER_FORWARD;
+      break;
+    case APPCOMMAND_BROWSER_REFRESH:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_BROWSER_REFRESH;
+      break;
+    case APPCOMMAND_BROWSER_STOP:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_BROWSER_STOP;
+      break;
+    case APPCOMMAND_BROWSER_SEARCH:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_BROWSER_SEARCH;
+      break;
+    case APPCOMMAND_BROWSER_FAVORITES:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_BROWSER_FAVORITES;
+      break;
+    case APPCOMMAND_BROWSER_HOME:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_BROWSER_HOME;
+      break;
+    case APPCOMMAND_VOLUME_MUTE:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_VOLUME_MUTE;
+      break;
+    case APPCOMMAND_VOLUME_DOWN:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_VOLUME_DOWN;
+      break;
+    case APPCOMMAND_VOLUME_UP:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_VOLUME_UP;
+      break;
+    case APPCOMMAND_MEDIA_NEXTTRACK:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_MEDIA_NEXT_TRACK;
+      break;
+    case APPCOMMAND_MEDIA_PREVIOUSTRACK:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_MEDIA_PREV_TRACK;
+      break;
+    case APPCOMMAND_MEDIA_STOP:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_MEDIA_STOP;
+      break;
+    case APPCOMMAND_MEDIA_PLAY_PAUSE:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_MEDIA_PLAY_PAUSE;
+      break;
+    case APPCOMMAND_LAUNCH_MAIL:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_LAUNCH_MAIL;
+      break;
+    case APPCOMMAND_LAUNCH_MEDIA_SELECT:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_LAUNCH_MEDIA_SELECT;
+      break;
+    case APPCOMMAND_LAUNCH_APP1:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_LAUNCH_APP1;
+      break;
+    case APPCOMMAND_LAUNCH_APP2:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_LAUNCH_APP2;
+      break;
+    default:
+      return;
+  }
+
+  uint16_t scanCodeEx = ComputeScanCodeExFromVirtualKeyCode(mVirtualKeyCode);
+  mScanCode = static_cast<uint8_t>(scanCodeEx & 0xFF);
+  uint8_t extended = static_cast<uint8_t>((scanCodeEx & 0xFF00) >> 8);
+  mIsExtended = (extended == 0xE0) || (extended == 0xE1);
+  mDOMKeyCode = KeyboardLayout::GetInstance()->ConvertNativeKeyCodeToDOMKeyCode(
+      mOriginalVirtualKeyCode);
+  mCodeNameIndex = KeyboardLayout::ConvertScanCodeToCodeNameIndex(
+      GetScanCodeWithExtendedFlag());
+  // If we can map the WM_APPCOMMAND to a virtual keycode, we can trust
+  // the result of GetKeyboardState().  Otherwise, we dispatch both
+  // keydown and keyup events from WM_APPCOMMAND handler.  Therefore,
+  // even if WM_APPCOMMAND is caused by auto key repeat, web apps receive
+  // a pair of DOM keydown and keyup events.  I.e., KeyboardEvent.repeat
+  // should be never true of such keys.
+  // XXX Isn't the key state always true?  If the key press caused this
+  //     WM_APPCOMMAND, that means it's pressed at that time.
+  if (mVirtualKeyCode) {
+    BYTE kbdState[256];
+    memset(kbdState, 0, sizeof(kbdState));
+    ::GetKeyboardState(kbdState);
+    mIsSkippableInRemoteProcess = mIsRepeat = !!kbdState[mVirtualKeyCode];
+  }
+}
+
+bool NativeKey::MaybeEmulatingAltGraph() const {
+  return IsControl() && IsAlt() && KeyboardLayout::GetInstance()->HasAltGr();
+}
+
+// static
+bool NativeKey::IsControlChar(char16_t aChar) {
+  static const char16_t U_SPACE = 0x20;
+  static const char16_t U_DELETE = 0x7F;
+  return aChar < U_SPACE || aChar == U_DELETE;
+}
+
+bool NativeKey::IsFollowedByDeadCharMessage() const {
+  if (mFollowingCharMsgs.IsEmpty()) {
+    return false;
+  }
+  return IsDeadCharMessage(mFollowingCharMsgs[0]);
+}
+
+bool NativeKey::IsFollowedByPrintableCharMessage() const {
+  for (size_t i = 0; i < mFollowingCharMsgs.Length(); ++i) {
+    if (IsPrintableCharMessage(mFollowingCharMsgs[i])) {
+      return true;
+    }
+  }
+  return false;
+}
+
+bool NativeKey::IsFollowedByPrintableCharOrSysCharMessage() const {
+  for (size_t i = 0; i < mFollowingCharMsgs.Length(); ++i) {
+    if (IsPrintableCharOrSysCharMessage(mFollowingCharMsgs[i])) {
+      return true;
+    }
+  }
+  return false;
+}
+
+bool NativeKey::IsReservedBySystem() const {
+  // Alt+Space key is handled by OS, we shouldn't touch it.
+  if (mModKeyState.IsAlt() && !mModKeyState.IsControl() &&
+      mVirtualKeyCode == VK_SPACE) {
+    return true;
+  }
+
+  // XXX How about Alt+F4? We receive WM_SYSKEYDOWN for F4 before closing the
+  //     window.  Although, we don't prevent to close the window but the key
+  //     event shouldn't be exposed to the web.
+
+  return false;
+}
+
+bool NativeKey::IsIMEDoingKakuteiUndo() const {
+  // Following message pattern is caused by "Kakutei-Undo" of ATOK or WXG:
+  // ---------------------------------------------------------------------------
+  // WM_KEYDOWN              * n (wParam = VK_BACK, lParam = 0x1)
+  // WM_KEYUP                * 1 (wParam = VK_BACK, lParam = 0xC0000001) # ATOK
+  // WM_IME_STARTCOMPOSITION * 1 (wParam = 0x0, lParam = 0x0)
+  // WM_IME_COMPOSITION      * 1 (wParam = 0x0, lParam = 0x1BF)
+  // WM_CHAR                 * n (wParam = VK_BACK, lParam = 0x1)
+  // WM_KEYUP                * 1 (wParam = VK_BACK, lParam = 0xC00E0001)
+  // ---------------------------------------------------------------------------
+  // This doesn't match usual key message pattern such as:
+  //   WM_KEYDOWN -> WM_CHAR -> WM_KEYDOWN -> WM_CHAR -> ... -> WM_KEYUP
+  // See following bugs for the detail.
+  // https://bugzilla.mozilla.gr.jp/show_bug.cgi?id=2885 (written in Japanese)
+  // https://bugzilla.mozilla.org/show_bug.cgi?id=194559 (written in English)
+  MSG startCompositionMsg, compositionMsg, charMsg;
+  return WinUtils::PeekMessage(&startCompositionMsg, mMsg.hwnd,
+                               WM_IME_STARTCOMPOSITION, WM_IME_STARTCOMPOSITION,
+                               PM_NOREMOVE | PM_NOYIELD) &&
+         WinUtils::PeekMessage(&compositionMsg, mMsg.hwnd, WM_IME_COMPOSITION,
+                               WM_IME_COMPOSITION, PM_NOREMOVE | PM_NOYIELD) &&
+         WinUtils::PeekMessage(&charMsg, mMsg.hwnd, WM_CHAR, WM_CHAR,
+                               PM_NOREMOVE | PM_NOYIELD) &&
+         startCompositionMsg.wParam == 0x0 &&
+         startCompositionMsg.lParam == 0x0 && compositionMsg.wParam == 0x0 &&
+         compositionMsg.lParam == 0x1BF && charMsg.wParam == VK_BACK &&
+         charMsg.lParam == 0x1 &&
+         startCompositionMsg.time <= compositionMsg.time &&
+         compositionMsg.time <= charMsg.time;
+}
+
+void NativeKey::RemoveFollowingOddCharMessages() {
+  MOZ_ASSERT(IsKeyDownMessage());
+
+  // If the keydown message is synthesized for automated tests, there is
+  // nothing to do here.
+  if (mFakeCharMsgs) {
+    return;
+  }
+
+  // If there are some following char messages before another key message,
+  // there is nothing to do here.
+  if (!mFollowingCharMsgs.IsEmpty()) {
+    return;
+  }
+
+  // If the handling key isn't Backspace, there is nothing to do here.
+  if (mOriginalVirtualKeyCode != VK_BACK) {
+    return;
+  }
+
+  // If we don't see the odd message pattern, there is nothing to do here.
+  if (!IsIMEDoingKakuteiUndo()) {
+    return;
+  }
+
+  // Otherwise, we need to remove odd WM_CHAR messages for ATOK or WXG (both
+  // of them are Japanese IME).
+  MSG msg;
+  while (WinUtils::PeekMessage(&msg, mMsg.hwnd, WM_CHAR, WM_CHAR,
+                               PM_REMOVE | PM_NOYIELD)) {
+    if (msg.message != WM_CHAR) {
+      MOZ_RELEASE_ASSERT(msg.message == WM_NULL,
+                         "Unexpected message was removed");
+      continue;
+    }
+    MOZ_LOG(
+        gKeyLog, LogLevel::Info,
+        ("%p   NativeKey::RemoveFollowingOddCharMessages(), removed odd char "
+         "message, %s",
+         this, ToString(msg).get()));
+    mRemovedOddCharMsgs.AppendElement(msg);
+  }
+}
+
+UINT NativeKey::GetScanCodeWithExtendedFlag() const {
+  if (!mIsExtended) {
+    return mScanCode;
+  }
+  return (0xE000 | mScanCode);
+}
+
+uint32_t NativeKey::GetKeyLocation() const {
+  switch (mVirtualKeyCode) {
+    case VK_LSHIFT:
+    case VK_LCONTROL:
+    case VK_LMENU:
+    case VK_LWIN:
+      return eKeyLocationLeft;
+
+    case VK_RSHIFT:
+    case VK_RCONTROL:
+    case VK_RMENU:
+    case VK_RWIN:
+      return eKeyLocationRight;
+
+    case VK_RETURN:
+      // XXX This code assumes that all keyboard drivers use same mapping.
+      return !mIsExtended ? eKeyLocationStandard : eKeyLocationNumpad;
+
+    case VK_INSERT:
+    case VK_DELETE:
+    case VK_END:
+    case VK_DOWN:
+    case VK_NEXT:
+    case VK_LEFT:
+    case VK_CLEAR:
+    case VK_RIGHT:
+    case VK_HOME:
+    case VK_UP:
+    case VK_PRIOR:
+      // XXX This code assumes that all keyboard drivers use same mapping.
+      return mIsExtended ? eKeyLocationStandard : eKeyLocationNumpad;
+
+    // NumLock key isn't included due to IE9's behavior.
+    case VK_NUMPAD0:
+    case VK_NUMPAD1:
+    case VK_NUMPAD2:
+    case VK_NUMPAD3:
+    case VK_NUMPAD4:
+    case VK_NUMPAD5:
+    case VK_NUMPAD6:
+    case VK_NUMPAD7:
+    case VK_NUMPAD8:
+    case VK_NUMPAD9:
+    case VK_DECIMAL:
+    case VK_DIVIDE:
+    case VK_MULTIPLY:
+    case VK_SUBTRACT:
+    case VK_ADD:
+    // Separator key of Brazilian keyboard or JIS keyboard for Mac
+    case VK_ABNT_C2:
+      return eKeyLocationNumpad;
+
+    case VK_SHIFT:
+    case VK_CONTROL:
+    case VK_MENU:
+      NS_WARNING("Failed to decide the key location?");
+      [[fallthrough]];
+
+    default:
+      return eKeyLocationStandard;
+  }
+}
+
+uint8_t NativeKey::ComputeVirtualKeyCodeFromScanCode() const {
+  return static_cast<uint8_t>(
+      ::MapVirtualKeyEx(mScanCode, MAPVK_VSC_TO_VK, mKeyboardLayout));
+}
+
+uint8_t NativeKey::ComputeVirtualKeyCodeFromScanCodeEx() const {
+  // MapVirtualKeyEx() has been improved for supporting extended keys since
+  // Vista.  When we call it for mapping a scancode of an extended key and
+  // a virtual keycode, we need to add 0xE000 to the scancode.
+  return static_cast<uint8_t>(::MapVirtualKeyEx(
+      GetScanCodeWithExtendedFlag(), MAPVK_VSC_TO_VK_EX, mKeyboardLayout));
+}
+
+uint16_t NativeKey::ComputeScanCodeExFromVirtualKeyCode(
+    UINT aVirtualKeyCode) const {
+  return static_cast<uint16_t>(
+      ::MapVirtualKeyEx(aVirtualKeyCode, MAPVK_VK_TO_VSC_EX, mKeyboardLayout));
+}
+
+char16_t NativeKey::ComputeUnicharFromScanCode() const {
+  return static_cast<char16_t>(::MapVirtualKeyEx(
+      ComputeVirtualKeyCodeFromScanCode(), MAPVK_VK_TO_CHAR, mKeyboardLayout));
+}
+
+nsEventStatus NativeKey::InitKeyEvent(WidgetKeyboardEvent& aKeyEvent) const {
+  return InitKeyEvent(aKeyEvent, mModKeyState);
+}
+
+nsEventStatus NativeKey::InitKeyEvent(
+    WidgetKeyboardEvent& aKeyEvent,
+    const ModifierKeyState& aModKeyState) const {
+  if (mWidget->Destroyed()) {
+    MOZ_CRASH("NativeKey tries to dispatch a key event on destroyed widget");
+  }
+
+  LayoutDeviceIntPoint point(0, 0);
+  mWidget->InitEvent(aKeyEvent, &point);
+
+  switch (aKeyEvent.mMessage) {
+    case eKeyDown:
+      // If it was followed by a char message but it was consumed by somebody,
+      // we should mark it as consumed because somebody must have handled it
+      // and we should prevent to do "double action" for the key operation.
+      // However, for compatibility with older version and other browsers,
+      // we should dispatch the events even in the web content.
+      if (mCharMessageHasGone) {
+        aKeyEvent.PreventDefaultBeforeDispatch(CrossProcessForwarding::eAllow);
+      }
+      aKeyEvent.mKeyCode = mDOMKeyCode;
+      // Unique id for this keydown event and its associated keypress.
+      sUniqueKeyEventId++;
+      aKeyEvent.mUniqueId = sUniqueKeyEventId;
+      break;
+    case eKeyUp:
+      aKeyEvent.mKeyCode = mDOMKeyCode;
+      // Set defaultPrevented of the key event if the VK_MENU is not a system
+      // key release, so that the menu bar does not trigger.  This helps avoid
+      // triggering the menu bar for ALT key accelerators used in assistive
+      // technologies such as Window-Eyes and ZoomText or for switching open
+      // state of IME.  On the other hand, we should dispatch the events even
+      // in the web content for compatibility with older version and other
+      // browsers.
+      if (mOriginalVirtualKeyCode == VK_MENU && mMsg.message != WM_SYSKEYUP) {
+        aKeyEvent.PreventDefaultBeforeDispatch(CrossProcessForwarding::eAllow);
+      }
+      break;
+    case eKeyPress:
+      MOZ_ASSERT(!mCharMessageHasGone,
+                 "If following char message was consumed by somebody, "
+                 "keydown event should be consumed above");
+      aKeyEvent.mUniqueId = sUniqueKeyEventId;
+      break;
+    default:
+      MOZ_CRASH("Invalid event message");
+  }
+
+  aKeyEvent.mIsRepeat = mIsRepeat;
+  aKeyEvent.mMaybeSkippableInRemoteProcess = mIsSkippableInRemoteProcess;
+  aKeyEvent.mKeyNameIndex = mKeyNameIndex;
+  if (mKeyNameIndex == KEY_NAME_INDEX_USE_STRING) {
+    aKeyEvent.mKeyValue = mCommittedCharsAndModifiers.ToString();
+  }
+  aKeyEvent.mCodeNameIndex = mCodeNameIndex;
+  MOZ_ASSERT(mCodeNameIndex != CODE_NAME_INDEX_USE_STRING);
+  aKeyEvent.mLocation = GetKeyLocation();
+  aModKeyState.InitInputEvent(aKeyEvent);
+
+  KeyboardLayout::NotifyIdleServiceOfUserActivity();
+
+  MOZ_LOG(
+      gKeyLog, LogLevel::Info,
+      ("%p   NativeKey::InitKeyEvent(), initialized, aKeyEvent={ "
+       "mMessage=%s, mKeyNameIndex=%s, mKeyValue=\"%s\", mCodeNameIndex=%s, "
+       "mKeyCode=%s, mLocation=%s, mModifiers=%s, DefaultPrevented()=%s }",
+       this, ToChar(aKeyEvent.mMessage),
+       ToString(aKeyEvent.mKeyNameIndex).get(),
+       NS_ConvertUTF16toUTF8(aKeyEvent.mKeyValue).get(),
+       ToString(aKeyEvent.mCodeNameIndex).get(),
+       GetDOMKeyCodeName(aKeyEvent.mKeyCode).get(),
+       GetKeyLocationName(aKeyEvent.mLocation).get(),
+       GetModifiersName(aKeyEvent.mModifiers).get(),
+       GetBoolName(aKeyEvent.DefaultPrevented())));
+
+  return aKeyEvent.DefaultPrevented() ? nsEventStatus_eConsumeNoDefault
+                                      : nsEventStatus_eIgnore;
+}
+
+bool NativeKey::DispatchCommandEvent(uint32_t aEventCommand) const {
+  RefPtr<nsAtom> command;
+  switch (aEventCommand) {
+    case APPCOMMAND_BROWSER_BACKWARD:
+      command = nsGkAtoms::Back;
+      break;
+    case APPCOMMAND_BROWSER_FORWARD:
+      command = nsGkAtoms::Forward;
+      break;
+    case APPCOMMAND_BROWSER_REFRESH:
+      command = nsGkAtoms::Reload;
+      break;
+    case APPCOMMAND_BROWSER_STOP:
+      command = nsGkAtoms::Stop;
+      break;
+    case APPCOMMAND_BROWSER_SEARCH:
+      command = nsGkAtoms::Search;
+      break;
+    case APPCOMMAND_BROWSER_FAVORITES:
+      command = nsGkAtoms::Bookmarks;
+      break;
+    case APPCOMMAND_BROWSER_HOME:
+      command = nsGkAtoms::Home;
+      break;
+    case APPCOMMAND_CLOSE:
+      command = nsGkAtoms::Close;
+      break;
+    case APPCOMMAND_FIND:
+      command = nsGkAtoms::Find;
+      break;
+    case APPCOMMAND_HELP:
+      command = nsGkAtoms::Help;
+      break;
+    case APPCOMMAND_NEW:
+      command = nsGkAtoms::New;
+      break;
+    case APPCOMMAND_OPEN:
+      command = nsGkAtoms::Open;
+      break;
+    case APPCOMMAND_PRINT:
+      command = nsGkAtoms::Print;
+      break;
+    case APPCOMMAND_SAVE:
+      command = nsGkAtoms::Save;
+      break;
+    case APPCOMMAND_FORWARD_MAIL:
+      command = nsGkAtoms::ForwardMail;
+      break;
+    case APPCOMMAND_REPLY_TO_MAIL:
+      command = nsGkAtoms::ReplyToMail;
+      break;
+    case APPCOMMAND_SEND_MAIL:
+      command = nsGkAtoms::SendMail;
+      break;
+    case APPCOMMAND_MEDIA_NEXTTRACK:
+      command = nsGkAtoms::NextTrack;
+      break;
+    case APPCOMMAND_MEDIA_PREVIOUSTRACK:
+      command = nsGkAtoms::PreviousTrack;
+      break;
+    case APPCOMMAND_MEDIA_STOP:
+      command = nsGkAtoms::MediaStop;
+      break;
+    case APPCOMMAND_MEDIA_PLAY_PAUSE:
+      command = nsGkAtoms::PlayPause;
+      break;
+    default:
+      MOZ_LOG(
+          gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::DispatchCommandEvent(), doesn't dispatch command "
+           "event",
+           this));
+      return false;
+  }
+  WidgetCommandEvent appCommandEvent(true, command, mWidget);
+
+  mWidget->InitEvent(appCommandEvent);
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::DispatchCommandEvent(), dispatching "
+           "%s app command event...",
+           this, nsAtomCString(command).get()));
+  bool ok =
+      mWidget->DispatchWindowEvent(appCommandEvent) || mWidget->Destroyed();
+  MOZ_LOG(
+      gKeyLog, LogLevel::Info,
+      ("%p   NativeKey::DispatchCommandEvent(), dispatched app command event, "
+       "result=%s, mWidget->Destroyed()=%s",
+       this, GetBoolName(ok), GetBoolName(mWidget->Destroyed())));
+  return ok;
+}
+
+bool NativeKey::HandleAppCommandMessage() const {
+  // If the widget has gone, we should do nothing.
+  if (mWidget->Destroyed()) {
+    MOZ_LOG(gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::HandleAppCommandMessage(), WARNING, not handled "
+             "due to "
+             "destroyed the widget",
+             this));
+    return false;
+  }
+
+  // NOTE: Typical behavior of WM_APPCOMMAND caused by key is, WM_APPCOMMAND
+  //       message is _sent_ first.  Then, the DefaultWndProc will _post_
+  //       WM_KEYDOWN message and WM_KEYUP message if the keycode for the
+  //       command is available (i.e., mVirtualKeyCode is not 0).
+
+  // NOTE: IntelliType (Microsoft's keyboard utility software) always consumes
+  //       WM_KEYDOWN and WM_KEYUP.
+
+  // Let's dispatch keydown message before our chrome handles the command
+  // when the message is caused by a keypress.  This behavior makes handling
+  // WM_APPCOMMAND be a default action of the keydown event.  This means that
+  // web applications can handle multimedia keys and prevent our default action.
+  // This allow web applications to provide better UX for multimedia keyboard
+  // users.
+  bool dispatchKeyEvent = (GET_DEVICE_LPARAM(mMsg.lParam) == FAPPCOMMAND_KEY);
+  if (dispatchKeyEvent) {
+    // If a plug-in window has focus but it didn't consume the message, our
+    // window receive WM_APPCOMMAND message.  In this case, we shouldn't
+    // dispatch KeyboardEvents because an event handler may access the
+    // plug-in process synchronously.
+    dispatchKeyEvent =
+        WinUtils::IsOurProcessWindow(reinterpret_cast<HWND>(mMsg.wParam));
+  }
+
+  bool consumed = false;
+
+  if (dispatchKeyEvent) {
+    nsresult rv = mDispatcher->BeginNativeInputTransaction();
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      MOZ_LOG(gKeyLog, LogLevel::Error,
+              ("%p   NativeKey::HandleAppCommandMessage(), FAILED due to "
+               "BeginNativeInputTransaction() failure",
+               this));
+      return true;
+    }
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleAppCommandMessage(), initializing keydown "
+             "event...",
+             this));
+    WidgetKeyboardEvent keydownEvent(true, eKeyDown, mWidget);
+    nsEventStatus status = InitKeyEvent(keydownEvent, mModKeyState);
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleAppCommandMessage(), tries to dispatch "
+             "keydown event...",
+             this));
+    // NOTE: If the keydown event is consumed by web contents, we shouldn't
+    //       continue to handle the command.
+    if (!mDispatcher->DispatchKeyboardEvent(eKeyDown, keydownEvent, status,
+                                            const_cast<NativeKey*>(this))) {
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("%p   NativeKey::HandleAppCommandMessage(), keydown event isn't "
+               "dispatched",
+               this));
+      // If keyboard event wasn't fired, there must be composition.
+      // So, we don't need to dispatch a command event.
+      return true;
+    }
+    consumed = status == nsEventStatus_eConsumeNoDefault;
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleAppCommandMessage(), keydown event was "
+             "dispatched, consumed=%s",
+             this, GetBoolName(consumed)));
+    sDispatchedKeyOfAppCommand = mVirtualKeyCode;
+    if (mWidget->Destroyed()) {
+      MOZ_LOG(
+          gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::HandleAppCommandMessage(), keydown event caused "
+           "destroying the widget",
+           this));
+      return true;
+    }
+  }
+
+  // Dispatch a command event or a content command event if the command is
+  // supported.
+  if (!consumed) {
+    uint32_t appCommand = GET_APPCOMMAND_LPARAM(mMsg.lParam);
+    EventMessage contentCommandMessage = eVoidEvent;
+    switch (appCommand) {
+      case APPCOMMAND_BROWSER_BACKWARD:
+      case APPCOMMAND_BROWSER_FORWARD:
+      case APPCOMMAND_BROWSER_REFRESH:
+      case APPCOMMAND_BROWSER_STOP:
+      case APPCOMMAND_BROWSER_SEARCH:
+      case APPCOMMAND_BROWSER_FAVORITES:
+      case APPCOMMAND_BROWSER_HOME:
+      case APPCOMMAND_CLOSE:
+      case APPCOMMAND_FIND:
+      case APPCOMMAND_HELP:
+      case APPCOMMAND_NEW:
+      case APPCOMMAND_OPEN:
+      case APPCOMMAND_PRINT:
+      case APPCOMMAND_SAVE:
+      case APPCOMMAND_FORWARD_MAIL:
+      case APPCOMMAND_REPLY_TO_MAIL:
+      case APPCOMMAND_SEND_MAIL:
+      case APPCOMMAND_MEDIA_NEXTTRACK:
+      case APPCOMMAND_MEDIA_PREVIOUSTRACK:
+      case APPCOMMAND_MEDIA_STOP:
+      case APPCOMMAND_MEDIA_PLAY_PAUSE:
+        // We shouldn't consume the message always because if we don't handle
+        // the message, the sender (typically, utility of keyboard or mouse)
+        // may send other key messages which indicate well known shortcut key.
+        consumed = DispatchCommandEvent(appCommand);
+        break;
+
+      // Use content command for following commands:
+      case APPCOMMAND_COPY:
+        contentCommandMessage = eContentCommandCopy;
+        break;
+      case APPCOMMAND_CUT:
+        contentCommandMessage = eContentCommandCut;
+        break;
+      case APPCOMMAND_PASTE:
+        contentCommandMessage = eContentCommandPaste;
+        break;
+      case APPCOMMAND_REDO:
+        contentCommandMessage = eContentCommandRedo;
+        break;
+      case APPCOMMAND_UNDO:
+        contentCommandMessage = eContentCommandUndo;
+        break;
+    }
+
+    if (contentCommandMessage) {
+      MOZ_ASSERT(!mWidget->Destroyed());
+      WidgetContentCommandEvent contentCommandEvent(true, contentCommandMessage,
+                                                    mWidget);
+      MOZ_LOG(
+          gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::HandleAppCommandMessage(), dispatching %s event...",
+           this, ToChar(contentCommandMessage)));
+      mWidget->DispatchWindowEvent(contentCommandEvent);
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("%p   NativeKey::HandleAppCommandMessage(), dispatched %s event",
+               this, ToChar(contentCommandMessage)));
+      consumed = true;
+
+      if (mWidget->Destroyed()) {
+        MOZ_LOG(gKeyLog, LogLevel::Info,
+                ("%p   NativeKey::HandleAppCommandMessage(), %s event caused "
+                 "destroying the widget",
+                 this, ToChar(contentCommandMessage)));
+        return true;
+      }
+    } else {
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("%p   NativeKey::HandleAppCommandMessage(), doesn't dispatch "
+               "content "
+               "command event",
+               this));
+    }
+  }
+
+  // Dispatch a keyup event if the command is caused by pressing a key and
+  // the key isn't mapped to a virtual keycode.
+  if (dispatchKeyEvent && !mVirtualKeyCode) {
+    MOZ_ASSERT(!mWidget->Destroyed());
+    nsresult rv = mDispatcher->BeginNativeInputTransaction();
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      MOZ_LOG(gKeyLog, LogLevel::Error,
+              ("%p   NativeKey::HandleAppCommandMessage(), FAILED due to "
+               "BeginNativeInputTransaction() failure",
+               this));
+      return true;
+    }
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleAppCommandMessage(), initializing keyup "
+             "event...",
+             this));
+    WidgetKeyboardEvent keyupEvent(true, eKeyUp, mWidget);
+    nsEventStatus status = InitKeyEvent(keyupEvent, mModKeyState);
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleAppCommandMessage(), dispatching keyup "
+             "event...",
+             this));
+    // NOTE: Ignore if the keyup event is consumed because keyup event
+    //       represents just a physical key event state change.
+    mDispatcher->DispatchKeyboardEvent(eKeyUp, keyupEvent, status,
+                                       const_cast<NativeKey*>(this));
+    MOZ_LOG(
+        gKeyLog, LogLevel::Info,
+        ("%p   NativeKey::HandleAppCommandMessage(), dispatched keyup event",
+         this));
+    if (mWidget->Destroyed()) {
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("%p   NativeKey::HandleAppCommandMessage(), keyup event caused "
+               "destroying the widget",
+               this));
+      return true;
+    }
+  }
+
+  return consumed;
+}
+
+bool NativeKey::HandleKeyDownMessage(bool* aEventDispatched) const {
+  MOZ_ASSERT(IsKeyDownMessage());
+
+  if (aEventDispatched) {
+    *aEventDispatched = false;
+  }
+
+  if (sDispatchedKeyOfAppCommand &&
+      sDispatchedKeyOfAppCommand == mOriginalVirtualKeyCode) {
+    // The multimedia key event has already been dispatch from
+    // HandleAppCommandMessage().
+    sDispatchedKeyOfAppCommand = 0;
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyDownMessage(), doesn't dispatch keydown "
+             "event due to already dispatched from HandleAppCommandMessage(), ",
+             this));
+    if (RedirectedKeyDownMessageManager::IsRedirectedMessage(mMsg)) {
+      RedirectedKeyDownMessageManager::Forget();
+    }
+    return true;
+  }
+
+  if (IsReservedBySystem()) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyDownMessage(), doesn't dispatch keydown "
+             "event because the key combination is reserved by the system",
+             this));
+    if (RedirectedKeyDownMessageManager::IsRedirectedMessage(mMsg)) {
+      RedirectedKeyDownMessageManager::Forget();
+    }
+    return false;
+  }
+
+  if (sPendingHighSurrogate) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyDownMessage(), doesn't dispatch keydown "
+             "event because the key introduced only a high surrotate, so we "
+             "should wait the following low surrogate input",
+             this));
+    if (RedirectedKeyDownMessageManager::IsRedirectedMessage(mMsg)) {
+      RedirectedKeyDownMessageManager::Forget();
+    }
+    return false;
+  }
+
+  // If the widget has gone, we should do nothing.
+  if (mWidget->Destroyed()) {
+    MOZ_LOG(
+        gKeyLog, LogLevel::Warning,
+        ("%p   NativeKey::HandleKeyDownMessage(), WARNING, not handled due to "
+         "destroyed the widget",
+         this));
+    if (RedirectedKeyDownMessageManager::IsRedirectedMessage(mMsg)) {
+      RedirectedKeyDownMessageManager::Forget();
+    }
+    return false;
+  }
+
+  bool defaultPrevented = false;
+  if (mFakeCharMsgs ||
+      !RedirectedKeyDownMessageManager::IsRedirectedMessage(mMsg)) {
+    nsresult rv = mDispatcher->BeginNativeInputTransaction();
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      MOZ_LOG(gKeyLog, LogLevel::Error,
+              ("%p   NativeKey::HandleKeyDownMessage(), FAILED due to "
+               "BeginNativeInputTransaction() failure",
+               this));
+      return true;
+    }
+
+    bool isIMEEnabled = WinUtils::IsIMEEnabled(mWidget->GetInputContext());
+
+    MOZ_LOG(gKeyLog, LogLevel::Debug,
+            ("%p   NativeKey::HandleKeyDownMessage(), initializing keydown "
+             "event...",
+             this));
+
+    WidgetKeyboardEvent keydownEvent(true, eKeyDown, mWidget);
+    nsEventStatus status = InitKeyEvent(keydownEvent, mModKeyState);
+    MOZ_LOG(
+        gKeyLog, LogLevel::Info,
+        ("%p   NativeKey::HandleKeyDownMessage(), dispatching keydown event...",
+         this));
+    bool dispatched = mDispatcher->DispatchKeyboardEvent(
+        eKeyDown, keydownEvent, status, const_cast<NativeKey*>(this));
+    if (aEventDispatched) {
+      *aEventDispatched = dispatched;
+    }
+    if (!dispatched) {
+      // If the keydown event wasn't fired, there must be composition.
+      // we don't need to do anything anymore.
+      MOZ_LOG(
+          gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::HandleKeyDownMessage(), doesn't dispatch keypress "
+           "event(s) because keydown event isn't dispatched actually",
+           this));
+      return false;
+    }
+    defaultPrevented = status == nsEventStatus_eConsumeNoDefault;
+
+    if (mWidget->Destroyed() || IsFocusedWindowChanged()) {
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("%p   NativeKey::HandleKeyDownMessage(), keydown event caused "
+               "destroying the widget",
+               this));
+      return true;
+    }
+
+    MOZ_LOG(
+        gKeyLog, LogLevel::Info,
+        ("%p   NativeKey::HandleKeyDownMessage(), dispatched keydown event, "
+         "dispatched=%s, defaultPrevented=%s",
+         this, GetBoolName(dispatched), GetBoolName(defaultPrevented)));
+
+    // If IMC wasn't associated to the window but is associated it now (i.e.,
+    // focus is moved from a non-editable editor to an editor by keydown
+    // event handler), WM_CHAR and WM_SYSCHAR shouldn't cause first character
+    // inputting if IME is opened.  But then, we should redirect the native
+    // keydown message to IME.
+    // However, note that if focus has been already moved to another
+    // application, we shouldn't redirect the message to it because the keydown
+    // message is processed by us, so, nobody shouldn't process it.
+    HWND focusedWnd = ::GetFocus();
+    if (!defaultPrevented && !mFakeCharMsgs && focusedWnd && !isIMEEnabled &&
+        WinUtils::IsIMEEnabled(mWidget->GetInputContext())) {
+      RedirectedKeyDownMessageManager::RemoveNextCharMessage(focusedWnd);
+
+      INPUT keyinput;
+      keyinput.type = INPUT_KEYBOARD;
+      keyinput.ki.wVk = mOriginalVirtualKeyCode;
+      keyinput.ki.wScan = mScanCode;
+      keyinput.ki.dwFlags = KEYEVENTF_SCANCODE;
+      if (mIsExtended) {
+        keyinput.ki.dwFlags |= KEYEVENTF_EXTENDEDKEY;
+      }
+      keyinput.ki.time = 0;
+      keyinput.ki.dwExtraInfo = 0;
+
+      RedirectedKeyDownMessageManager::WillRedirect(mMsg, defaultPrevented);
+
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("%p   NativeKey::HandleKeyDownMessage(), redirecting %s...",
+               this, ToString(mMsg).get()));
+
+      ::SendInput(1, &keyinput, sizeof(keyinput));
+
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("%p   NativeKey::HandleKeyDownMessage(), redirected %s", this,
+               ToString(mMsg).get()));
+
+      // Return here.  We shouldn't dispatch keypress event for this WM_KEYDOWN.
+      // If it's needed, it will be dispatched after next (redirected)
+      // WM_KEYDOWN.
+      return true;
+    }
+  } else {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyDownMessage(), received a redirected %s",
+             this, ToString(mMsg).get()));
+
+    defaultPrevented = RedirectedKeyDownMessageManager::DefaultPrevented();
+    // If this is redirected keydown message, we have dispatched the keydown
+    // event already.
+    if (aEventDispatched) {
+      *aEventDispatched = true;
+    }
+  }
+
+  RedirectedKeyDownMessageManager::Forget();
+
+  MOZ_ASSERT(!mWidget->Destroyed());
+
+  // If the key was processed by IME and didn't cause WM_(SYS)CHAR messages, we
+  // shouldn't dispatch keypress event.
+  if (mOriginalVirtualKeyCode == VK_PROCESSKEY &&
+      !IsFollowedByPrintableCharOrSysCharMessage()) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyDownMessage(), not dispatching keypress "
+             "event because the key was already handled by IME, "
+             "defaultPrevented=%s",
+             this, GetBoolName(defaultPrevented)));
+    return defaultPrevented;
+  }
+
+  if (defaultPrevented) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyDownMessage(), not dispatching keypress "
+             "event because preceding keydown event was consumed",
+             this));
+    return true;
+  }
+
+  MOZ_ASSERT(!mCharMessageHasGone,
+             "If following char message was consumed by somebody, "
+             "keydown event should have been consumed before dispatch");
+
+  // If mCommittedCharsAndModifiers was initialized with following char
+  // messages, we should dispatch keypress events with its information.
+  if (IsFollowedByPrintableCharOrSysCharMessage()) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyDownMessage(), tries to be dispatching "
+             "keypress events with retrieved char messages...",
+             this));
+    return DispatchKeyPressEventsWithRetrievedCharMessages();
+  }
+
+  // If we won't be getting a WM_CHAR, WM_SYSCHAR or WM_DEADCHAR, synthesize a
+  // keypress for almost all keys
+  if (NeedsToHandleWithoutFollowingCharMessages()) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyDownMessage(), tries to be dispatching "
+             "keypress events...",
+             this));
+    return DispatchKeyPressEventsWithoutCharMessage();
+  }
+
+  // If WM_KEYDOWN of VK_PACKET isn't followed by WM_CHAR, we don't need to
+  // dispatch keypress events.
+  if (mVirtualKeyCode == VK_PACKET) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyDownMessage(), not dispatching keypress "
+             "event "
+             "because the key is VK_PACKET and there are no char messages",
+             this));
+    return false;
+  }
+
+  if (!mModKeyState.IsControl() && !mModKeyState.IsAlt() &&
+      !mModKeyState.IsWin() && mIsPrintableKey) {
+    // If this is simple KeyDown event but next message is not WM_CHAR,
+    // this event may not input text, so we should ignore this event.
+    // See bug 314130.
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyDownMessage(), not dispatching keypress "
+             "event "
+             "because the key event is simple printable key's event but not "
+             "followed "
+             "by char messages",
+             this));
+    return false;
+  }
+
+  if (mIsDeadKey) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyDownMessage(), not dispatching keypress "
+             "event "
+             "because the key is a dead key and not followed by char messages",
+             this));
+    return false;
+  }
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::HandleKeyDownMessage(), tries to be dispatching "
+           "keypress events due to no following char messages...",
+           this));
+  return DispatchKeyPressEventsWithoutCharMessage();
+}
+
+bool NativeKey::HandleCharMessage(bool* aEventDispatched) const {
+  MOZ_ASSERT(IsCharOrSysCharMessage(mMsg));
+  return HandleCharMessage(mMsg, aEventDispatched);
+}
+
+bool NativeKey::HandleCharMessage(const MSG& aCharMsg,
+                                  bool* aEventDispatched) const {
+  MOZ_ASSERT(IsKeyDownMessage() || IsCharOrSysCharMessage(mMsg));
+  MOZ_ASSERT(IsCharOrSysCharMessage(aCharMsg.message));
+
+  if (aEventDispatched) {
+    *aEventDispatched = false;
+  }
+
+  if ((IsCharOrSysCharMessage(mMsg) || IsEnterKeyPressCharMessage(mMsg)) &&
+      IsAnotherInstanceRemovingCharMessage()) {
+    MOZ_LOG(
+        gKeyLog, LogLevel::Warning,
+        ("%p   NativeKey::HandleCharMessage(), WARNING, does nothing because "
+         "the message should be handled in another instance removing this "
+         "message",
+         this));
+    // Consume this for now because it will be handled by another instance.
+    return true;
+  }
+
+  // If the key combinations is reserved by the system, we shouldn't dispatch
+  // eKeyPress event for it and passes the message to next wndproc.
+  if (IsReservedBySystem()) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleCharMessage(), doesn't dispatch keypress "
+             "event because the key combination is reserved by the system",
+             this));
+    return false;
+  }
+
+  // If the widget has gone, we should do nothing.
+  if (mWidget->Destroyed()) {
+    MOZ_LOG(gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::HandleCharMessage(), WARNING, not handled due to "
+             "destroyed the widget",
+             this));
+    return false;
+  }
+
+  // When a control key is inputted by a key, it should be handled without
+  // WM_*CHAR messages at receiving WM_*KEYDOWN message.  So, when we receive
+  // WM_*CHAR message directly, we see a control character here.
+  // Note that when the char is '\r', it means that the char message should
+  // cause "Enter" keypress event for inserting a line break.
+  if (IsControlCharMessage(aCharMsg) && !IsEnterKeyPressCharMessage(aCharMsg)) {
+    // In this case, we don't need to dispatch eKeyPress event because:
+    // 1. We're the only browser which dispatches "keypress" event for
+    //    non-printable characters (Although, both Chrome and Edge dispatch
+    //    "keypress" event for some keys accidentally.  For example, "IntlRo"
+    //    key with Ctrl of Japanese keyboard layout).
+    // 2. Currently, we may handle shortcut keys with "keydown" event if
+    //    it's reserved or something.  So, we shouldn't dispatch "keypress"
+    //    event without it.
+    // Note that this does NOT mean we stop dispatching eKeyPress event for
+    // key presses causes a control character when Ctrl is pressed.  In such
+    // case, DispatchKeyPressEventsWithoutCharMessage() dispatches eKeyPress
+    // instead of this method.
+    MOZ_LOG(
+        gKeyLog, LogLevel::Info,
+        ("%p   NativeKey::HandleCharMessage(), doesn't dispatch keypress "
+         "event because received a control character input without WM_KEYDOWN",
+         this));
+    return false;
+  }
+
+  // XXXmnakano I think that if mMsg is WM_CHAR, i.e., it comes without
+  //            preceding WM_KEYDOWN, we should should dispatch composition
+  //            events instead of eKeyPress because they are not caused by
+  //            actual keyboard operation.
+
+  // First, handle normal text input or non-printable key case here.
+  WidgetKeyboardEvent keypressEvent(true, eKeyPress, mWidget);
+  if (IsEnterKeyPressCharMessage(aCharMsg)) {
+    keypressEvent.mKeyCode = NS_VK_RETURN;
+  } else {
+    keypressEvent.mCharCode = static_cast<uint32_t>(aCharMsg.wParam);
+  }
+  nsresult rv = mDispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gKeyLog, LogLevel::Error,
+            ("%p   NativeKey::HandleCharMessage(), FAILED due to "
+             "BeginNativeInputTransaction() failure",
+             this));
+    return true;
+  }
+
+  MOZ_LOG(gKeyLog, LogLevel::Debug,
+          ("%p   NativeKey::HandleCharMessage(), initializing keypress "
+           "event...",
+           this));
+
+  ModifierKeyState modKeyState(mModKeyState);
+  // When AltGr is pressed, both Alt and Ctrl are active.  However, when they
+  // are active, TextEditor won't treat the keypress event as inputting a
+  // character.  Therefore, when AltGr is pressed and the key tries to input
+  // a character, let's set them to false.
+  if (modKeyState.IsControl() && modKeyState.IsAlt() &&
+      IsPrintableCharMessage(aCharMsg)) {
+    modKeyState.Unset(MODIFIER_ALT | MODIFIER_CONTROL);
+  }
+  nsEventStatus status = InitKeyEvent(keypressEvent, modKeyState);
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::HandleCharMessage(), dispatching keypress event...",
+           this));
+  bool dispatched = mDispatcher->MaybeDispatchKeypressEvents(
+      keypressEvent, status, const_cast<NativeKey*>(this));
+  if (aEventDispatched) {
+    *aEventDispatched = dispatched;
+  }
+  if (mWidget->Destroyed()) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleCharMessage(), keypress event caused "
+             "destroying the widget",
+             this));
+    return true;
+  }
+  bool consumed = status == nsEventStatus_eConsumeNoDefault;
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::HandleCharMessage(), dispatched keypress event, "
+           "dispatched=%s, consumed=%s",
+           this, GetBoolName(dispatched), GetBoolName(consumed)));
+  return consumed;
+}
+
+bool NativeKey::HandleKeyUpMessage(bool* aEventDispatched) const {
+  MOZ_ASSERT(IsKeyUpMessage());
+
+  if (aEventDispatched) {
+    *aEventDispatched = false;
+  }
+
+  // If the key combinations is reserved by the system, we shouldn't dispatch
+  // eKeyUp event for it and passes the message to next wndproc.
+  if (IsReservedBySystem()) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyUpMessage(), doesn't dispatch keyup "
+             "event because the key combination is reserved by the system",
+             this));
+    return false;
+  }
+
+  if (sPendingHighSurrogate) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyUpMessage(), doesn't dispatch keyup "
+             "event because the key introduced only a high surrotate, so we "
+             "should wait the following low surrogate input",
+             this));
+    return false;
+  }
+
+  // If the widget has gone, we should do nothing.
+  if (mWidget->Destroyed()) {
+    MOZ_LOG(
+        gKeyLog, LogLevel::Warning,
+        ("%p   NativeKey::HandleKeyUpMessage(), WARNING, not handled due to "
+         "destroyed the widget",
+         this));
+    return false;
+  }
+
+  nsresult rv = mDispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gKeyLog, LogLevel::Error,
+            ("%p   NativeKey::HandleKeyUpMessage(), FAILED due to "
+             "BeginNativeInputTransaction() failure",
+             this));
+    return true;
+  }
+
+  MOZ_LOG(gKeyLog, LogLevel::Debug,
+          ("%p   NativeKey::HandleKeyUpMessage(), initializing keyup event...",
+           this));
+  WidgetKeyboardEvent keyupEvent(true, eKeyUp, mWidget);
+  nsEventStatus status = InitKeyEvent(keyupEvent, mModKeyState);
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::HandleKeyUpMessage(), dispatching keyup event...",
+           this));
+  bool dispatched = mDispatcher->DispatchKeyboardEvent(
+      eKeyUp, keyupEvent, status, const_cast<NativeKey*>(this));
+  if (aEventDispatched) {
+    *aEventDispatched = dispatched;
+  }
+  if (mWidget->Destroyed()) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyUpMessage(), keyup event caused "
+             "destroying the widget",
+             this));
+    return true;
+  }
+  bool consumed = status == nsEventStatus_eConsumeNoDefault;
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::HandleKeyUpMessage(), dispatched keyup event, "
+           "dispatched=%s, consumed=%s",
+           this, GetBoolName(dispatched), GetBoolName(consumed)));
+  return consumed;
+}
+
+bool NativeKey::NeedsToHandleWithoutFollowingCharMessages() const {
+  MOZ_ASSERT(IsKeyDownMessage());
+
+  // If the key combination is reserved by the system, the caller shouldn't
+  // do anything with following WM_*CHAR messages.  So, let's return true here.
+  if (IsReservedBySystem()) {
+    return true;
+  }
+
+  // If the keydown message is generated for inputting some Unicode characters
+  // via SendInput() API, we need to handle it only with WM_*CHAR messages.
+  if (mVirtualKeyCode == VK_PACKET) {
+    return false;
+  }
+
+  // If following char message is for a control character, it should be handled
+  // without WM_CHAR message.  This is typically Ctrl + [a-z].
+  if (mFollowingCharMsgs.Length() == 1 &&
+      IsControlCharMessage(mFollowingCharMsgs[0])) {
+    return true;
+  }
+
+  // If keydown message is followed by WM_CHAR or WM_SYSCHAR whose wParam isn't
+  // a control character, we should dispatch keypress event with the char
+  // message even with any modifier state.
+  if (IsFollowedByPrintableCharOrSysCharMessage()) {
+    return false;
+  }
+
+  // If any modifier keys which may cause printable keys becoming non-printable
+  // are not pressed, we don't need special handling for the key.
+  // Note that if the key does not produce a character with AltGr and when
+  // AltGr key is pressed, we don't need to dispatch eKeyPress event for it
+  // because AltGr shouldn't be used for a modifier for a shortcut without
+  // Ctrl, Alt or Win.  That means that we should treat it in same path for
+  // Shift key.
+  if (!mModKeyState.IsControl() && !mModKeyState.IsAlt() &&
+      !mModKeyState.IsWin()) {
+    return false;
+  }
+
+  // If the key event causes dead key event, we don't need to dispatch keypress
+  // event.
+  if (mIsDeadKey && mCommittedCharsAndModifiers.IsEmpty()) {
+    return false;
+  }
+
+  // Even if the key is a printable key, it might cause non-printable character
+  // input with modifier key(s).
+  return mIsPrintableKey;
+}
+
+static nsCString GetResultOfInSendMessageEx() {
+  DWORD ret = ::InSendMessageEx(nullptr);
+  if (!ret) {
+    return "ISMEX_NOSEND"_ns;
+  }
+  nsCString result;
+  if (ret & ISMEX_CALLBACK) {
+    result = "ISMEX_CALLBACK";
+  }
+  if (ret & ISMEX_NOTIFY) {
+    if (!result.IsEmpty()) {
+      result += " | ";
+    }
+    result += "ISMEX_NOTIFY";
+  }
+  if (ret & ISMEX_REPLIED) {
+    if (!result.IsEmpty()) {
+      result += " | ";
+    }
+    result += "ISMEX_REPLIED";
+  }
+  if (ret & ISMEX_SEND) {
+    if (!result.IsEmpty()) {
+      result += " | ";
+    }
+    result += "ISMEX_SEND";
+  }
+  return result;
+}
+
+bool NativeKey::MayBeSameCharMessage(const MSG& aCharMsg1,
+                                     const MSG& aCharMsg2) const {
+  // NOTE: Although, we don't know when this case occurs, the scan code value
+  //       in lParam may be changed from 0 to something.  The changed value
+  //       is different from the scan code of handling keydown message.
+  static const LPARAM kScanCodeMask = 0x00FF0000;
+  return aCharMsg1.message == aCharMsg2.message &&
+         aCharMsg1.wParam == aCharMsg2.wParam &&
+         (aCharMsg1.lParam & ~kScanCodeMask) ==
+             (aCharMsg2.lParam & ~kScanCodeMask);
+}
+
+bool NativeKey::IsSamePhysicalKeyMessage(const MSG& aKeyOrCharMsg1,
+                                         const MSG& aKeyOrCharMsg2) const {
+  if (NS_WARN_IF(aKeyOrCharMsg1.message < WM_KEYFIRST) ||
+      NS_WARN_IF(aKeyOrCharMsg1.message > WM_KEYLAST) ||
+      NS_WARN_IF(aKeyOrCharMsg2.message < WM_KEYFIRST) ||
+      NS_WARN_IF(aKeyOrCharMsg2.message > WM_KEYLAST)) {
+    return false;
+  }
+  return WinUtils::GetScanCode(aKeyOrCharMsg1.lParam) ==
+             WinUtils::GetScanCode(aKeyOrCharMsg2.lParam) &&
+         WinUtils::IsExtendedScanCode(aKeyOrCharMsg1.lParam) ==
+             WinUtils::IsExtendedScanCode(aKeyOrCharMsg2.lParam);
+}
+
+bool NativeKey::GetFollowingCharMessage(MSG& aCharMsg) {
+  MOZ_ASSERT(IsKeyDownMessage());
+
+  aCharMsg.message = WM_NULL;
+
+  if (mFakeCharMsgs) {
+    for (size_t i = 0; i < mFakeCharMsgs->Length(); i++) {
+      FakeCharMsg& fakeCharMsg = mFakeCharMsgs->ElementAt(i);
+      if (fakeCharMsg.mConsumed) {
+        continue;
+      }
+      MSG charMsg = fakeCharMsg.GetCharMsg(mMsg.hwnd);
+      fakeCharMsg.mConsumed = true;
+      if (!IsCharMessage(charMsg)) {
+        return false;
+      }
+      aCharMsg = charMsg;
+      return true;
+    }
+    return false;
+  }
+
+  // If next key message is not char message, we should give up to find a
+  // related char message for the handling keydown event for now.
+  // Note that it's possible other applications may send other key message
+  // after we call TranslateMessage(). That may cause PeekMessage() failing
+  // to get char message for the handling keydown message.
+  MSG nextKeyMsg;
+  if (!WinUtils::PeekMessage(&nextKeyMsg, mMsg.hwnd, WM_KEYFIRST, WM_KEYLAST,
+                             PM_NOREMOVE | PM_NOYIELD) ||
+      !IsCharMessage(nextKeyMsg)) {
+    MOZ_LOG(gKeyLog, LogLevel::Debug,
+            ("%p   NativeKey::GetFollowingCharMessage(), there are no char "
+             "messages",
+             this));
+    return false;
+  }
+  const MSG kFoundCharMsg = nextKeyMsg;
+
+  AutoRestore<MSG> saveLastRemovingMsg(mRemovingMsg);
+  mRemovingMsg = nextKeyMsg;
+
+  mReceivedMsg = sEmptyMSG;
+  AutoRestore<MSG> ensureToClearRecivedMsg(mReceivedMsg);
+
+  // On Metrofox, PeekMessage() sometimes returns WM_NULL even if we specify
+  // the message range.  So, if it returns WM_NULL, we should retry to get
+  // the following char message it was found above.
+  for (uint32_t i = 0; i < 50; i++) {
+    MSG removedMsg, nextKeyMsgInAllWindows;
+    bool doCrash = false;
+    if (!WinUtils::PeekMessage(&removedMsg, mMsg.hwnd, nextKeyMsg.message,
+                               nextKeyMsg.message, PM_REMOVE | PM_NOYIELD)) {
+      // We meets unexpected case.  We should collect the message queue state
+      // and crash for reporting the bug.
+      doCrash = true;
+
+      // If another instance was created for the removing message during trying
+      // to remove a char message, the instance didn't handle it for preventing
+      // recursive handling.  So, let's handle it in this instance.
+      if (!IsEmptyMSG(mReceivedMsg)) {
+        // If focus is moved to different window, we shouldn't handle it on
+        // the widget.  Let's discard it for now.
+        if (mReceivedMsg.hwnd != nextKeyMsg.hwnd) {
+          MOZ_LOG(
+              gKeyLog, LogLevel::Warning,
+              ("%p   NativeKey::GetFollowingCharMessage(), WARNING, received a "
+               "char message during removing it from the queue, but it's for "
+               "different window, mReceivedMsg=%s, nextKeyMsg=%s, "
+               "kFoundCharMsg=%s",
+               this, ToString(mReceivedMsg).get(), ToString(nextKeyMsg).get(),
+               ToString(kFoundCharMsg).get()));
+          // There might still exist char messages, the loop of calling
+          // this method should be continued.
+          aCharMsg.message = WM_NULL;
+          return true;
+        }
+        // Even if the received message is different from what we tried to
+        // remove from the queue, let's take the received message as a part of
+        // the result of this key sequence.
+        if (mReceivedMsg.message != nextKeyMsg.message ||
+            mReceivedMsg.wParam != nextKeyMsg.wParam ||
+            mReceivedMsg.lParam != nextKeyMsg.lParam) {
+          MOZ_LOG(
+              gKeyLog, LogLevel::Warning,
+              ("%p   NativeKey::GetFollowingCharMessage(), WARNING, received a "
+               "char message during removing it from the queue, but it's "
+               "differnt from what trying to remove from the queue, "
+               "aCharMsg=%s, nextKeyMsg=%s, kFoundCharMsg=%s",
+               this, ToString(mReceivedMsg).get(), ToString(nextKeyMsg).get(),
+               ToString(kFoundCharMsg).get()));
+        } else {
+          MOZ_LOG(
+              gKeyLog, LogLevel::Debug,
+              ("%p   NativeKey::GetFollowingCharMessage(), succeeded to "
+               "retrieve next char message via another instance, aCharMsg=%s, "
+               "kFoundCharMsg=%s",
+               this, ToString(mReceivedMsg).get(),
+               ToString(kFoundCharMsg).get()));
+        }
+        aCharMsg = mReceivedMsg;
+        return true;
+      }
+
+      // The char message is redirected to different thread's window by focus
+      // move or something or just cancelled by external application.
+      if (!WinUtils::PeekMessage(&nextKeyMsgInAllWindows, 0, WM_KEYFIRST,
+                                 WM_KEYLAST, PM_NOREMOVE | PM_NOYIELD)) {
+        MOZ_LOG(
+            gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::GetFollowingCharMessage(), WARNING, failed to "
+             "remove a char message, but it's already gone from all message "
+             "queues, nextKeyMsg=%s, kFoundCharMsg=%s",
+             this, ToString(nextKeyMsg).get(), ToString(kFoundCharMsg).get()));
+        return true;  // XXX should return false in this case
+      }
+      // The next key message is redirected to different window created by our
+      // thread, we should do nothing because we must not have focus.
+      if (nextKeyMsgInAllWindows.hwnd != mMsg.hwnd) {
+        aCharMsg = nextKeyMsgInAllWindows;
+        MOZ_LOG(
+            gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::GetFollowingCharMessage(), WARNING, failed to "
+             "remove a char message, but found in another message queue, "
+             "nextKeyMsgInAllWindows=%s, nextKeyMsg=%s, kFoundCharMsg=%s",
+             this, ToString(nextKeyMsgInAllWindows).get(),
+             ToString(nextKeyMsg).get(), ToString(kFoundCharMsg).get()));
+        return true;
+      }
+      // If next key message becomes non-char message, this key operation
+      // may have already been consumed or canceled.
+      if (!IsCharMessage(nextKeyMsgInAllWindows)) {
+        MOZ_LOG(
+            gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::GetFollowingCharMessage(), WARNING, failed to "
+             "remove a char message and next key message becomes non-char "
+             "message, nextKeyMsgInAllWindows=%s, nextKeyMsg=%s, "
+             "kFoundCharMsg=%s",
+             this, ToString(nextKeyMsgInAllWindows).get(),
+             ToString(nextKeyMsg).get(), ToString(kFoundCharMsg).get()));
+        MOZ_ASSERT(!mCharMessageHasGone);
+        mFollowingCharMsgs.Clear();
+        mCharMessageHasGone = true;
+        return false;
+      }
+      // If next key message is still a char message but different key message,
+      // we should treat current key operation is consumed or canceled and
+      // next char message should be handled as an orphan char message later.
+      if (!IsSamePhysicalKeyMessage(nextKeyMsgInAllWindows, kFoundCharMsg)) {
+        MOZ_LOG(
+            gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::GetFollowingCharMessage(), WARNING, failed to "
+             "remove a char message and next key message becomes differnt "
+             "key's "
+             "char message, nextKeyMsgInAllWindows=%s, nextKeyMsg=%s, "
+             "kFoundCharMsg=%s",
+             this, ToString(nextKeyMsgInAllWindows).get(),
+             ToString(nextKeyMsg).get(), ToString(kFoundCharMsg).get()));
+        MOZ_ASSERT(!mCharMessageHasGone);
+        mFollowingCharMsgs.Clear();
+        mCharMessageHasGone = true;
+        return false;
+      }
+      // If next key message is still a char message but the message is changed,
+      // we should retry to remove the new message with PeekMessage() again.
+      if (nextKeyMsgInAllWindows.message != nextKeyMsg.message) {
+        MOZ_LOG(
+            gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::GetFollowingCharMessage(), WARNING, failed to "
+             "remove a char message due to message change, let's retry to "
+             "remove the message with newly found char message, "
+             "nextKeyMsgInAllWindows=%s, nextKeyMsg=%s, kFoundCharMsg=%s",
+             this, ToString(nextKeyMsgInAllWindows).get(),
+             ToString(nextKeyMsg).get(), ToString(kFoundCharMsg).get()));
+        nextKeyMsg = nextKeyMsgInAllWindows;
+        continue;
+      }
+      // If there is still existing a char message caused by same physical key
+      // in the queue but PeekMessage(PM_REMOVE) failed to remove it from the
+      // queue, it might be possible that the odd keyboard layout or utility
+      // hooks only PeekMessage(PM_NOREMOVE) and GetMessage().  So, let's try
+      // remove the char message with GetMessage() again.
+      // FYI: The wParam might be different from the found message, but it's
+      //      okay because we assume that odd keyboard layouts return actual
+      //      inputting character at removing the char message.
+      if (WinUtils::GetMessage(&removedMsg, mMsg.hwnd, nextKeyMsg.message,
+                               nextKeyMsg.message)) {
+        MOZ_LOG(
+            gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::GetFollowingCharMessage(), WARNING, failed to "
+             "remove a char message, but succeeded with GetMessage(), "
+             "removedMsg=%s, kFoundCharMsg=%s",
+             this, ToString(removedMsg).get(), ToString(kFoundCharMsg).get()));
+        // Cancel to crash, but we need to check the removed message value.
+        doCrash = false;
+      }
+      // If we've already removed some WM_NULL messages from the queue and
+      // the found message has already gone from the queue, let's treat the key
+      // as inputting no characters and already consumed.
+      else if (i > 0) {
+        MOZ_LOG(
+            gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::GetFollowingCharMessage(), WARNING, failed to "
+             "remove a char message, but removed %d WM_NULL messages",
+             this, i));
+        // If the key is a printable key or a control key but tried to input
+        // a character, mark mCharMessageHasGone true for handling the keydown
+        // event as inputting empty string.
+        MOZ_ASSERT(!mCharMessageHasGone);
+        mFollowingCharMsgs.Clear();
+        mCharMessageHasGone = true;
+        return false;
+      }
+      MOZ_LOG(gKeyLog, LogLevel::Error,
+              ("%p   NativeKey::GetFollowingCharMessage(), FAILED, lost target "
+               "message to remove, nextKeyMsg=%s",
+               this, ToString(nextKeyMsg).get()));
+    }
+
+    if (doCrash) {
+      nsPrintfCString info(
+          "\nPeekMessage() failed to remove char message! "
+          "\nActive keyboard layout=0x%p (%s), "
+          "\nHandling message: %s, InSendMessageEx()=%s, "
+          "\nFound message: %s, "
+          "\nWM_NULL has been removed: %d, "
+          "\nNext key message in all windows: %s, "
+          "time=%ld, ",
+          KeyboardLayout::GetInstance()->GetLoadedLayout(),
+          KeyboardLayout::GetInstance()->GetLoadedLayoutName().get(),
+          ToString(mMsg).get(), GetResultOfInSendMessageEx().get(),
+          ToString(kFoundCharMsg).get(), i,
+          ToString(nextKeyMsgInAllWindows).get(), nextKeyMsgInAllWindows.time);
+      CrashReporter::AppendAppNotesToCrashReport(info);
+      MSG nextMsg;
+      if (WinUtils::PeekMessage(&nextMsg, 0, 0, 0, PM_NOREMOVE | PM_NOYIELD)) {
+        nsPrintfCString info("\nNext message in all windows: %s, time=%ld",
+                             ToString(nextMsg).get(), nextMsg.time);
+        CrashReporter::AppendAppNotesToCrashReport(info);
+      } else {
+        CrashReporter::AppendAppNotesToCrashReport(
+            "\nThere is no message in any window"_ns);
+      }
+
+      MOZ_CRASH("We lost the following char message");
+    }
+
+    // We're still not sure why ::PeekMessage() may return WM_NULL even with
+    // its first message and its last message are same message.  However,
+    // at developing Metrofox, we met this case even with usual keyboard
+    // layouts.  So, it might be possible in desktop application or it really
+    // occurs with some odd keyboard layouts which perhaps hook API.
+    if (removedMsg.message == WM_NULL) {
+      MOZ_LOG(gKeyLog, LogLevel::Warning,
+              ("%p   NativeKey::GetFollowingCharMessage(), WARNING, failed to "
+               "remove a char message, instead, removed WM_NULL message, "
+               "removedMsg=%s",
+               this, ToString(removedMsg).get()));
+      // Check if there is the message which we're trying to remove.
+      MSG newNextKeyMsg;
+      if (!WinUtils::PeekMessage(&newNextKeyMsg, mMsg.hwnd, WM_KEYFIRST,
+                                 WM_KEYLAST, PM_NOREMOVE | PM_NOYIELD)) {
+        // If there is no key message, we should mark this keydown as consumed
+        // because the key operation may have already been handled or canceled.
+        MOZ_LOG(
+            gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::GetFollowingCharMessage(), WARNING, failed to "
+             "remove a char message because it's gone during removing it from "
+             "the queue, nextKeyMsg=%s, kFoundCharMsg=%s",
+             this, ToString(nextKeyMsg).get(), ToString(kFoundCharMsg).get()));
+        MOZ_ASSERT(!mCharMessageHasGone);
+        mFollowingCharMsgs.Clear();
+        mCharMessageHasGone = true;
+        return false;
+      }
+      if (!IsCharMessage(newNextKeyMsg)) {
+        // If next key message becomes a non-char message, we should mark this
+        // keydown as consumed because the key operation may have already been
+        // handled or canceled.
+        MOZ_LOG(
+            gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::GetFollowingCharMessage(), WARNING, failed to "
+             "remove a char message because it's gone during removing it from "
+             "the queue, nextKeyMsg=%s, newNextKeyMsg=%s, kFoundCharMsg=%s",
+             this, ToString(nextKeyMsg).get(), ToString(newNextKeyMsg).get(),
+             ToString(kFoundCharMsg).get()));
+        MOZ_ASSERT(!mCharMessageHasGone);
+        mFollowingCharMsgs.Clear();
+        mCharMessageHasGone = true;
+        return false;
+      }
+      MOZ_LOG(
+          gKeyLog, LogLevel::Debug,
+          ("%p   NativeKey::GetFollowingCharMessage(), there is the message "
+           "which is being tried to be removed from the queue, trying again...",
+           this));
+      continue;
+    }
+
+    // Typically, this case occurs with WM_DEADCHAR.  If the removed message's
+    // wParam becomes 0, that means that the key event shouldn't cause text
+    // input.  So, let's ignore the strange char message.
+    if (removedMsg.message == nextKeyMsg.message && !removedMsg.wParam) {
+      MOZ_LOG(
+          gKeyLog, LogLevel::Warning,
+          ("%p   NativeKey::GetFollowingCharMessage(), WARNING, succeeded to "
+           "remove a char message, but the removed message's wParam is 0, "
+           "removedMsg=%s",
+           this, ToString(removedMsg).get()));
+      return false;
+    }
+
+    // This is normal case.
+    if (MayBeSameCharMessage(removedMsg, nextKeyMsg)) {
+      aCharMsg = removedMsg;
+      MOZ_LOG(
+          gKeyLog, LogLevel::Debug,
+          ("%p   NativeKey::GetFollowingCharMessage(), succeeded to retrieve "
+           "next char message, aCharMsg=%s",
+           this, ToString(aCharMsg).get()));
+      return true;
+    }
+
+    // Even if removed message is different char message from the found char
+    // message, when the scan code is same, we can assume that the message
+    // is overwritten by somebody who hooks API.  See bug 1336028 comment 0 for
+    // the possible scenarios.
+    if (IsCharMessage(removedMsg) &&
+        IsSamePhysicalKeyMessage(removedMsg, nextKeyMsg)) {
+      aCharMsg = removedMsg;
+      MOZ_LOG(
+          gKeyLog, LogLevel::Warning,
+          ("%p   NativeKey::GetFollowingCharMessage(), WARNING, succeeded to "
+           "remove a char message, but the removed message was changed from "
+           "the found message except their scancode, aCharMsg=%s, "
+           "nextKeyMsg=%s, kFoundCharMsg=%s",
+           this, ToString(aCharMsg).get(), ToString(nextKeyMsg).get(),
+           ToString(kFoundCharMsg).get()));
+      return true;
+    }
+
+    // When found message's wParam is 0 and its scancode is 0xFF, we may remove
+    // usual char message actually.  In such case, we should use the removed
+    // char message.
+    if (IsCharMessage(removedMsg) && !nextKeyMsg.wParam &&
+        WinUtils::GetScanCode(nextKeyMsg.lParam) == 0xFF) {
+      aCharMsg = removedMsg;
+      MOZ_LOG(
+          gKeyLog, LogLevel::Warning,
+          ("%p   NativeKey::GetFollowingCharMessage(), WARNING, succeeded to "
+           "remove a char message, but the removed message was changed from "
+           "the found message but the found message was odd, so, ignoring the "
+           "odd found message and respecting the removed message, aCharMsg=%s, "
+           "nextKeyMsg=%s, kFoundCharMsg=%s",
+           this, ToString(aCharMsg).get(), ToString(nextKeyMsg).get(),
+           ToString(kFoundCharMsg).get()));
+      return true;
+    }
+
+    // NOTE: Although, we don't know when this case occurs, the scan code value
+    //       in lParam may be changed from 0 to something.  The changed value
+    //       is different from the scan code of handling keydown message.
+    MOZ_LOG(
+        gKeyLog, LogLevel::Error,
+        ("%p   NativeKey::GetFollowingCharMessage(), FAILED, removed message "
+         "is really different from what we have already found, removedMsg=%s, "
+         "nextKeyMsg=%s, kFoundCharMsg=%s",
+         this, ToString(removedMsg).get(), ToString(nextKeyMsg).get(),
+         ToString(kFoundCharMsg).get()));
+    nsPrintfCString info(
+        "\nPeekMessage() removed unexpcted char message! "
+        "\nActive keyboard layout=0x%p (%s), "
+        "\nHandling message: %s, InSendMessageEx()=%s, "
+        "\nFound message: %s, "
+        "\nRemoved message: %s, ",
+        KeyboardLayout::GetInstance()->GetLoadedLayout(),
+        KeyboardLayout::GetInstance()->GetLoadedLayoutName().get(),
+        ToString(mMsg).get(), GetResultOfInSendMessageEx().get(),
+        ToString(kFoundCharMsg).get(), ToString(removedMsg).get());
+    CrashReporter::AppendAppNotesToCrashReport(info);
+    // What's the next key message?
+    MSG nextKeyMsgAfter;
+    if (WinUtils::PeekMessage(&nextKeyMsgAfter, mMsg.hwnd, WM_KEYFIRST,
+                              WM_KEYLAST, PM_NOREMOVE | PM_NOYIELD)) {
+      nsPrintfCString info(
+          "\nNext key message after unexpected char message "
+          "removed: %s, ",
+          ToString(nextKeyMsgAfter).get());
+      CrashReporter::AppendAppNotesToCrashReport(info);
+    } else {
+      CrashReporter::AppendAppNotesToCrashReport(
+          nsLiteralCString("\nThere is no key message after unexpected char "
+                           "message removed, "));
+    }
+    // Another window has a key message?
+    if (WinUtils::PeekMessage(&nextKeyMsgInAllWindows, 0, WM_KEYFIRST,
+                              WM_KEYLAST, PM_NOREMOVE | PM_NOYIELD)) {
+      nsPrintfCString info("\nNext key message in all windows: %s.",
+                           ToString(nextKeyMsgInAllWindows).get());
+      CrashReporter::AppendAppNotesToCrashReport(info);
+    } else {
+      CrashReporter::AppendAppNotesToCrashReport(
+          "\nThere is no key message in any windows."_ns);
+    }
+
+    MOZ_CRASH("PeekMessage() removed unexpected message");
+  }
+  MOZ_LOG(
+      gKeyLog, LogLevel::Error,
+      ("%p   NativeKey::GetFollowingCharMessage(), FAILED, removed messages "
+       "are all WM_NULL, nextKeyMsg=%s",
+       this, ToString(nextKeyMsg).get()));
+  nsPrintfCString info(
+      "\nWe lost following char message! "
+      "\nActive keyboard layout=0x%p (%s), "
+      "\nHandling message: %s, InSendMessageEx()=%s, \n"
+      "Found message: %s, removed a lot of WM_NULL",
+      KeyboardLayout::GetInstance()->GetLoadedLayout(),
+      KeyboardLayout::GetInstance()->GetLoadedLayoutName().get(),
+      ToString(mMsg).get(), GetResultOfInSendMessageEx().get(),
+      ToString(kFoundCharMsg).get());
+  CrashReporter::AppendAppNotesToCrashReport(info);
+  MOZ_CRASH("We lost the following char message");
+  return false;
+}
+
+void NativeKey::ComputeInputtingStringWithKeyboardLayout() {
+  KeyboardLayout* keyboardLayout = KeyboardLayout::GetInstance();
+
+  if (KeyboardLayout::IsPrintableCharKey(mVirtualKeyCode) ||
+      mCharMessageHasGone) {
+    mInputtingStringAndModifiers = mCommittedCharsAndModifiers;
+  } else {
+    mInputtingStringAndModifiers.Clear();
+  }
+  mShiftedString.Clear();
+  mUnshiftedString.Clear();
+  mShiftedLatinChar = mUnshiftedLatinChar = 0;
+
+  // XXX How about when Win key is pressed?
+  if (!mModKeyState.IsControl() && !mModKeyState.IsAlt()) {
+    return;
+  }
+
+  // If user is inputting a Unicode character with typing Alt + Numpad
+  // keys, we shouldn't set alternative key codes because the key event
+  // shouldn't match with a mnemonic.  However, we should set only
+  // mUnshiftedString for keeping traditional behavior at WM_SYSKEYDOWN.
+  // FYI: I guess that it's okay that mUnshiftedString stays empty.  So,
+  //      if its value breaks something, you must be able to just return here.
+  if (MaybeTypingUnicodeScalarValue()) {
+    if (!mCommittedCharsAndModifiers.IsEmpty()) {
+      MOZ_ASSERT(mMsg.message == WM_SYSKEYDOWN);
+      char16_t num = mCommittedCharsAndModifiers.CharAt(0);
+      MOZ_ASSERT(num >= '0' && num <= '9');
+      mUnshiftedString.Append(num, MODIFIER_NONE);
+      return;
+    }
+    // If user presses a function key without NumLock or 3rd party utility
+    // synthesizes a function key on numpad, we should handle it as-is because
+    // the user's intention may be performing `Alt` + foo.
+    MOZ_ASSERT(!KeyboardLayout::IsPrintableCharKey(mVirtualKeyCode));
+    return;
+  }
+
+  ModifierKeyState capsLockState(mModKeyState.GetModifiers() &
+                                 MODIFIER_CAPSLOCK);
+
+  mUnshiftedString =
+      keyboardLayout->GetUniCharsAndModifiers(mVirtualKeyCode, capsLockState);
+  capsLockState.Set(MODIFIER_SHIFT);
+  mShiftedString =
+      keyboardLayout->GetUniCharsAndModifiers(mVirtualKeyCode, capsLockState);
+
+  // The current keyboard cannot input alphabets or numerics,
+  // we should append them for Shortcut/Access keys.
+  // E.g., for Cyrillic keyboard layout.
+  capsLockState.Unset(MODIFIER_SHIFT);
+  WidgetUtils::GetLatinCharCodeForKeyCode(
+      mDOMKeyCode, capsLockState.GetModifiers(), &mUnshiftedLatinChar,
+      &mShiftedLatinChar);
+
+  // If the mShiftedLatinChar isn't 0, the key code is NS_VK_[A-Z].
+  if (mShiftedLatinChar) {
+    // If the produced characters of the key on current keyboard layout
+    // are same as computed Latin characters, we shouldn't append the
+    // Latin characters to alternativeCharCode.
+    if (mUnshiftedLatinChar == mUnshiftedString.CharAt(0) &&
+        mShiftedLatinChar == mShiftedString.CharAt(0)) {
+      mShiftedLatinChar = mUnshiftedLatinChar = 0;
+    }
+  } else if (mUnshiftedLatinChar) {
+    // If the mShiftedLatinChar is 0, the mKeyCode doesn't produce
+    // alphabet character.  At that time, the character may be produced
+    // with Shift key.  E.g., on French keyboard layout, NS_VK_PERCENT
+    // key produces LATIN SMALL LETTER U WITH GRAVE (U+00F9) without
+    // Shift key but with Shift key, it produces '%'.
+    // If the mUnshiftedLatinChar is produced by the key on current
+    // keyboard layout, we shouldn't append it to alternativeCharCode.
+    if (mUnshiftedLatinChar == mUnshiftedString.CharAt(0) ||
+        mUnshiftedLatinChar == mShiftedString.CharAt(0)) {
+      mUnshiftedLatinChar = 0;
+    }
+  }
+
+  if (!mModKeyState.IsControl()) {
+    return;
+  }
+
+  // If the mCharCode is not ASCII character, we should replace the
+  // mCharCode with ASCII character only when Ctrl is pressed.
+  // But don't replace the mCharCode when the mCharCode is not same as
+  // unmodified characters. In such case, Ctrl is sometimes used for a
+  // part of character inputting key combination like Shift.
+  uint32_t ch =
+      mModKeyState.IsShift() ? mShiftedLatinChar : mUnshiftedLatinChar;
+  if (!ch) {
+    return;
+  }
+  if (mInputtingStringAndModifiers.IsEmpty() ||
+      mInputtingStringAndModifiers.UniCharsCaseInsensitiveEqual(
+          mModKeyState.IsShift() ? mShiftedString : mUnshiftedString)) {
+    mInputtingStringAndModifiers.Clear();
+    mInputtingStringAndModifiers.Append(ch, mModKeyState.GetModifiers());
+  }
+}
+
+bool NativeKey::DispatchKeyPressEventsWithRetrievedCharMessages() const {
+  MOZ_ASSERT(IsKeyDownMessage());
+  MOZ_ASSERT(IsFollowedByPrintableCharOrSysCharMessage());
+  MOZ_ASSERT(!mWidget->Destroyed());
+
+  nsresult rv = mDispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(
+        gKeyLog, LogLevel::Error,
+        ("%p   NativeKey::DispatchKeyPressEventsWithRetrievedCharMessages(), "
+         "FAILED due to BeginNativeInputTransaction() failure",
+         this));
+    return true;
+  }
+  WidgetKeyboardEvent keypressEvent(true, eKeyPress, mWidget);
+  MOZ_LOG(gKeyLog, LogLevel::Debug,
+          ("%p   NativeKey::DispatchKeyPressEventsWithRetrievedCharMessages(), "
+           "initializing keypress event...",
+           this));
+  ModifierKeyState modKeyState(mModKeyState);
+  if (mCanIgnoreModifierStateAtKeyPress && IsFollowedByPrintableCharMessage()) {
+    // If eKeyPress event should cause inputting text in focused editor,
+    // we need to remove Alt and Ctrl state.
+    modKeyState.Unset(MODIFIER_ALT | MODIFIER_CONTROL);
+  }
+  // We don't need to send char message here if there are two or more retrieved
+  // messages because we need to set each message to each eKeyPress event.
+  bool needsCallback = mFollowingCharMsgs.Length() > 1;
+  nsEventStatus status = InitKeyEvent(keypressEvent, modKeyState);
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::DispatchKeyPressEventsWithRetrievedCharMessages(), "
+           "dispatching keypress event(s)...",
+           this));
+  bool dispatched = mDispatcher->MaybeDispatchKeypressEvents(
+      keypressEvent, status, const_cast<NativeKey*>(this), needsCallback);
+  if (mWidget->Destroyed()) {
+    MOZ_LOG(
+        gKeyLog, LogLevel::Info,
+        ("%p   NativeKey::DispatchKeyPressEventsWithRetrievedCharMessages(), "
+         "keypress event(s) caused destroying the widget",
+         this));
+    return true;
+  }
+  bool consumed = status == nsEventStatus_eConsumeNoDefault;
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::DispatchKeyPressEventsWithRetrievedCharMessages(), "
+           "dispatched keypress event(s), dispatched=%s, consumed=%s",
+           this, GetBoolName(dispatched), GetBoolName(consumed)));
+  return consumed;
+}
+
+bool NativeKey::DispatchKeyPressEventsWithoutCharMessage() const {
+  MOZ_ASSERT(IsKeyDownMessage());
+  MOZ_ASSERT(!mIsDeadKey || !mCommittedCharsAndModifiers.IsEmpty());
+  MOZ_ASSERT(!mWidget->Destroyed());
+
+  nsresult rv = mDispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gKeyLog, LogLevel::Error,
+            ("%p   NativeKey::DispatchKeyPressEventsWithoutCharMessage(), "
+             "FAILED due "
+             "to BeginNativeInputTransaction() failure",
+             this));
+    return true;
+  }
+
+  WidgetKeyboardEvent keypressEvent(true, eKeyPress, mWidget);
+  if (mInputtingStringAndModifiers.IsEmpty() && mShiftedString.IsEmpty() &&
+      mUnshiftedString.IsEmpty()) {
+    keypressEvent.mKeyCode = mDOMKeyCode;
+  }
+  MOZ_LOG(gKeyLog, LogLevel::Debug,
+          ("%p   NativeKey::DispatchKeyPressEventsWithoutCharMessage(), "
+           "initializing "
+           "keypress event...",
+           this));
+  nsEventStatus status = InitKeyEvent(keypressEvent, mModKeyState);
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::DispatchKeyPressEventsWithoutCharMessage(), "
+           "dispatching "
+           "keypress event(s)...",
+           this));
+  bool dispatched = mDispatcher->MaybeDispatchKeypressEvents(
+      keypressEvent, status, const_cast<NativeKey*>(this));
+  if (mWidget->Destroyed()) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::DispatchKeyPressEventsWithoutCharMessage(), "
+             "keypress event(s) caused destroying the widget",
+             this));
+    return true;
+  }
+  bool consumed = status == nsEventStatus_eConsumeNoDefault;
+  MOZ_LOG(
+      gKeyLog, LogLevel::Info,
+      ("%p   NativeKey::DispatchKeyPressEventsWithoutCharMessage(), dispatched "
+       "keypress event(s), dispatched=%s, consumed=%s",
+       this, GetBoolName(dispatched), GetBoolName(consumed)));
+  return consumed;
+}
+
+void NativeKey::WillDispatchKeyboardEvent(WidgetKeyboardEvent& aKeyboardEvent,
+                                          uint32_t aIndex) {
+  // If it's an eKeyPress event and it's generated from retrieved char message,
+  // we need to set raw message information for plugins.
+  if (aKeyboardEvent.mMessage == eKeyPress &&
+      IsFollowedByPrintableCharOrSysCharMessage()) {
+    MOZ_RELEASE_ASSERT(aIndex < mCommittedCharsAndModifiers.Length());
+    uint32_t foundPrintableCharMessages = 0;
+    for (size_t i = 0; i < mFollowingCharMsgs.Length(); ++i) {
+      if (!IsPrintableCharOrSysCharMessage(mFollowingCharMsgs[i])) {
+        // XXX Should we dispatch a plugin event for WM_*DEADCHAR messages and
+        //     WM_CHAR with a control character here?  But we're not sure
+        //     how can we create such message queue (i.e., WM_CHAR or
+        //     WM_SYSCHAR with a printable character and such message are
+        //     generated by a keydown).  So, let's ignore such case until
+        //     we'd get some bug reports.
+        MOZ_LOG(gKeyLog, LogLevel::Warning,
+                ("%p   NativeKey::WillDispatchKeyboardEvent(), WARNING, "
+                 "ignoring %zuth message due to non-printable char message, %s",
+                 this, i + 1, ToString(mFollowingCharMsgs[i]).get()));
+        continue;
+      }
+      if (foundPrintableCharMessages++ == aIndex) {
+        // Found message which caused the eKeyPress event.
+        break;
+      }
+    }
+    // Set modifier state from mCommittedCharsAndModifiers because some of them
+    // might be different.  For example, Shift key was pressed at inputting
+    // dead char but Shift key was released before inputting next character.
+    if (mCanIgnoreModifierStateAtKeyPress) {
+      ModifierKeyState modKeyState(mModKeyState);
+      modKeyState.Unset(MODIFIER_SHIFT | MODIFIER_CONTROL | MODIFIER_ALT |
+                        MODIFIER_ALTGRAPH | MODIFIER_CAPSLOCK);
+      modKeyState.Set(mCommittedCharsAndModifiers.ModifiersAt(aIndex));
+      modKeyState.InitInputEvent(aKeyboardEvent);
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("%p   NativeKey::WillDispatchKeyboardEvent(), "
+               "setting %uth modifier state to %s",
+               this, aIndex + 1, ToString(modKeyState).get()));
+    }
+  }
+  size_t longestLength =
+      std::max(mInputtingStringAndModifiers.Length(),
+               std::max(mShiftedString.Length(), mUnshiftedString.Length()));
+  size_t skipUniChars = longestLength - mInputtingStringAndModifiers.Length();
+  size_t skipShiftedChars = longestLength - mShiftedString.Length();
+  size_t skipUnshiftedChars = longestLength - mUnshiftedString.Length();
+  if (aIndex >= longestLength) {
+    MOZ_LOG(
+        gKeyLog, LogLevel::Info,
+        ("%p   NativeKey::WillDispatchKeyboardEvent(), does nothing for %uth "
+         "%s event",
+         this, aIndex + 1, ToChar(aKeyboardEvent.mMessage)));
+    return;
+  }
+
+  // Check if aKeyboardEvent is the last event for a key press.
+  // So, if it's not an eKeyPress event, it's always the last event.
+  // Otherwise, check if the index is the last character of
+  // mCommittedCharsAndModifiers.
+  bool isLastIndex = aKeyboardEvent.mMessage != eKeyPress ||
+                     mCommittedCharsAndModifiers.IsEmpty() ||
+                     mCommittedCharsAndModifiers.Length() - 1 == aIndex;
+
+  nsTArray<AlternativeCharCode>& altArray =
+      aKeyboardEvent.mAlternativeCharCodes;
+
+  // Set charCode and adjust modifier state for every eKeyPress event.
+  // This is not necessary for the other keyboard events because the other
+  // keyboard events shouldn't have non-zero charCode value and should have
+  // current modifier state.
+  if (aKeyboardEvent.mMessage == eKeyPress && skipUniChars <= aIndex) {
+    // XXX Modifying modifier state of aKeyboardEvent is illegal, but no way
+    //     to set different modifier state per keypress event except this
+    //     hack.  Note that ideally, dead key should cause composition events
+    //     instead of keypress events, though.
+    if (aIndex - skipUniChars < mInputtingStringAndModifiers.Length()) {
+      ModifierKeyState modKeyState(mModKeyState);
+      // If key in combination with Alt and/or Ctrl produces a different
+      // character than without them then do not report these flags
+      // because it is separate keyboard layout shift state. If dead-key
+      // and base character does not produce a valid composite character
+      // then both produced dead-key character and following base
+      // character may have different modifier flags, too.
+      modKeyState.Unset(MODIFIER_SHIFT | MODIFIER_CONTROL | MODIFIER_ALT |
+                        MODIFIER_ALTGRAPH | MODIFIER_CAPSLOCK);
+      modKeyState.Set(
+          mInputtingStringAndModifiers.ModifiersAt(aIndex - skipUniChars));
+      modKeyState.InitInputEvent(aKeyboardEvent);
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("%p   NativeKey::WillDispatchKeyboardEvent(), "
+               "setting %uth modifier state to %s",
+               this, aIndex + 1, ToString(modKeyState).get()));
+    }
+    uint16_t uniChar =
+        mInputtingStringAndModifiers.CharAt(aIndex - skipUniChars);
+
+    // The mCharCode was set from mKeyValue. However, for example, when Ctrl key
+    // is pressed, its value should indicate an ASCII character for backward
+    // compatibility rather than inputting character without the modifiers.
+    // Therefore, we need to modify mCharCode value here.
+    aKeyboardEvent.SetCharCode(uniChar);
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::WillDispatchKeyboardEvent(), "
+             "setting %uth charCode to %s",
+             this, aIndex + 1, GetCharacterCodeName(uniChar).get()));
+  }
+
+  // We need to append alterntaive charCode values:
+  //   - if the event is eKeyPress, we need to append for the index because
+  //     eKeyPress event is dispatched for every character inputted by a
+  //     key press.
+  //   - if the event is not eKeyPress, we need to append for all characters
+  //     inputted by the key press because the other keyboard events (e.g.,
+  //     eKeyDown are eKeyUp) are fired only once for a key press.
+  size_t count;
+  if (aKeyboardEvent.mMessage == eKeyPress) {
+    // Basically, append alternative charCode values only for the index.
+    count = 1;
+    // However, if it's the last eKeyPress event but different shift state
+    // can input longer string, the last eKeyPress event should have all
+    // remaining alternative charCode values.
+    if (isLastIndex) {
+      count = longestLength - aIndex;
+    }
+  } else {
+    count = longestLength;
+  }
+  for (size_t i = 0; i < count; ++i) {
+    uint16_t shiftedChar = 0, unshiftedChar = 0;
+    if (skipShiftedChars <= aIndex + i) {
+      shiftedChar = mShiftedString.CharAt(aIndex + i - skipShiftedChars);
+    }
+    if (skipUnshiftedChars <= aIndex + i) {
+      unshiftedChar = mUnshiftedString.CharAt(aIndex + i - skipUnshiftedChars);
+    }
+
+    if (shiftedChar || unshiftedChar) {
+      AlternativeCharCode chars(unshiftedChar, shiftedChar);
+      altArray.AppendElement(chars);
+    }
+
+    if (!isLastIndex) {
+      continue;
+    }
+
+    if (mUnshiftedLatinChar || mShiftedLatinChar) {
+      AlternativeCharCode chars(mUnshiftedLatinChar, mShiftedLatinChar);
+      altArray.AppendElement(chars);
+    }
+
+    // Typically, following virtual keycodes are used for a key which can
+    // input the character.  However, these keycodes are also used for
+    // other keys on some keyboard layout.  E.g., in spite of Shift+'1'
+    // inputs '+' on Thai keyboard layout, a key which is at '=/+'
+    // key on ANSI keyboard layout is VK_OEM_PLUS.  Native applications
+    // handle it as '+' key if Ctrl key is pressed.
+    char16_t charForOEMKeyCode = 0;
+    switch (mVirtualKeyCode) {
+      case VK_OEM_PLUS:
+        charForOEMKeyCode = '+';
+        break;
+      case VK_OEM_COMMA:
+        charForOEMKeyCode = ',';
+        break;
+      case VK_OEM_MINUS:
+        charForOEMKeyCode = '-';
+        break;
+      case VK_OEM_PERIOD:
+        charForOEMKeyCode = '.';
+        break;
+    }
+    if (charForOEMKeyCode && charForOEMKeyCode != mUnshiftedString.CharAt(0) &&
+        charForOEMKeyCode != mShiftedString.CharAt(0) &&
+        charForOEMKeyCode != mUnshiftedLatinChar &&
+        charForOEMKeyCode != mShiftedLatinChar) {
+      AlternativeCharCode OEMChars(charForOEMKeyCode, charForOEMKeyCode);
+      altArray.AppendElement(OEMChars);
+    }
+  }
+}
+
+/*****************************************************************************
+ * mozilla::widget::KeyboardLayout
+ *****************************************************************************/
+
+KeyboardLayout* KeyboardLayout::sInstance = nullptr;
+StaticRefPtr<nsIUserIdleServiceInternal> KeyboardLayout::sIdleService;
+
+// static
+KeyboardLayout* KeyboardLayout::GetInstance() {
+  if (!sInstance) {
+    sInstance = new KeyboardLayout();
+  }
+  return sInstance;
+}
+
+// static
+void KeyboardLayout::Shutdown() {
+  delete sInstance;
+  sInstance = nullptr;
+  sIdleService = nullptr;
+}
+
+// static
+void KeyboardLayout::NotifyIdleServiceOfUserActivity() {
+  if (!sIdleService) {
+    sIdleService = nsCOMPtr<nsIUserIdleServiceInternal>(
+                       do_GetService("@mozilla.org/widget/useridleservice;1"))
+                       .forget();
+    if (NS_WARN_IF(!sIdleService)) {
+      return;
+    }
+  }
+  sIdleService->ResetIdleTimeOut(0);
+}
+
+KeyboardLayout::KeyboardLayout() {
+  mDeadKeyTableListHead = nullptr;
+  // A dead key sequence should be made from up to 5 keys.  Therefore, 4 is
+  // enough and makes sense because the item is uint8_t.
+  // (Although, even if it's possible to be 6 keys or more in a sequence,
+  // this array will be re-allocated).
+  mActiveDeadKeys.SetCapacity(4);
+  mDeadKeyShiftStates.SetCapacity(4);
+
+  // If we put it off to load active keyboard layout when first needed, we need
+  // to load it at instanciation.  That makes us save the cost of a call of
+  // GetKeyboardLayout() API.
+  if (StaticPrefs::ui_key_layout_load_when_first_needed()) {
+    OnLayoutChange(::GetKeyboardLayout(0));
+  }
+}
+
+KeyboardLayout::~KeyboardLayout() { ReleaseDeadKeyTables(); }
+
+bool KeyboardLayout::IsPrintableCharKey(uint8_t aVirtualKey) {
+  return GetKeyIndex(aVirtualKey) >= 0;
+}
+
+WORD KeyboardLayout::ComputeScanCodeForVirtualKeyCode(
+    uint8_t aVirtualKeyCode) const {
+  return static_cast<WORD>(::MapVirtualKeyEx(aVirtualKeyCode, MAPVK_VK_TO_VSC,
+                                             KeyboardLayout::GetLayout()));
+}
+
+bool KeyboardLayout::IsDeadKey(uint8_t aVirtualKey,
+                               const ModifierKeyState& aModKeyState) const {
+  int32_t virtualKeyIndex = GetKeyIndex(aVirtualKey);
+
+  // XXX KeyboardLayout class doesn't support unusual keyboard layout which
+  //     maps some function keys as dead keys.
+  if (virtualKeyIndex < 0) {
+    return false;
+  }
+
+  return mVirtualKeys[virtualKeyIndex].IsDeadKey(
+      VirtualKey::ModifiersToShiftState(aModKeyState.GetModifiers()));
+}
+
+bool KeyboardLayout::IsSysKey(uint8_t aVirtualKey,
+                              const ModifierKeyState& aModKeyState) const {
+  // If Alt key is not pressed, it's never a system key combination.
+  // Additionally, if Ctrl key is pressed, it's never a system key combination
+  // too.
+  // FYI: Windows logo key state won't affect if it's a system key.
+  if (!aModKeyState.IsAlt() || aModKeyState.IsControl()) {
+    return false;
+  }
+
+  int32_t virtualKeyIndex = GetKeyIndex(aVirtualKey);
+  if (virtualKeyIndex < 0) {
+    return true;
+  }
+
+  UniCharsAndModifiers inputCharsAndModifiers =
+      GetUniCharsAndModifiers(aVirtualKey, aModKeyState);
+  if (inputCharsAndModifiers.IsEmpty()) {
+    return true;
+  }
+
+  // If the Alt key state isn't consumed, that means that the key with Alt
+  // doesn't cause text input.  So, the combination is a system key.
+  return !!(inputCharsAndModifiers.ModifiersAt(0) & MODIFIER_ALT);
+}
+
+void KeyboardLayout::InitNativeKey(NativeKey& aNativeKey) {
+  if (mIsPendingToRestoreKeyboardLayout) {
+    LoadLayout(::GetKeyboardLayout(0));
+  }
+
+  // If the aNativeKey is initialized with WM_CHAR, the key information
+  // should be discarded because mKeyValue should have the string to be
+  // inputted.
+  if (aNativeKey.mMsg.message == WM_CHAR) {
+    char16_t ch = static_cast<char16_t>(aNativeKey.mMsg.wParam);
+    // But don't set key value as printable key if the character is a control
+    // character such as 0x0D at pressing Enter key.
+    if (!NativeKey::IsControlChar(ch)) {
+      aNativeKey.mKeyNameIndex = KEY_NAME_INDEX_USE_STRING;
+      Modifiers modifiers =
+          aNativeKey.GetModifiers() & ~(MODIFIER_ALT | MODIFIER_CONTROL);
+      aNativeKey.mCommittedCharsAndModifiers.Append(ch, modifiers);
+      return;
+    }
+  }
+
+  // If the aNativeKey is in a sequence to input a Unicode character with
+  // Alt + numpad keys, we should just set the number as the inputting charcter.
+  // Note that we should compute the key value from the virtual key code
+  // because they may be mapped to alphabets, but they should be treated as
+  // Alt + [0-9] even by web apps.
+  // However, we shouldn't touch the key value if given virtual key code is
+  // not a printable key because it may be synthesized by 3rd party utility
+  // or just NumLock is unlocked and user tries to use shortcut key.  In the
+  // latter case, we cannot solve the conflict issue with Alt+foo shortcut key
+  // and inputting a Unicode scalar value like reported to bug 1606655, though,
+  // I have no better idea.  Perhaps, `Alt` shouldn't be used for shortcut key
+  // combination on Windows.
+  if (aNativeKey.MaybeTypingUnicodeScalarValue() &&
+      KeyboardLayout::IsPrintableCharKey(aNativeKey.mVirtualKeyCode)) {
+    // If the key code value is mapped to a Numpad key, let's compute the key
+    // value with it.  This is same behavior as Chrome.  In strictly speaking,
+    // I think that the else block's computation is better because it seems
+    // that Windows does not refer virtual key code value, but we should avoid
+    // web-compat issues.
+    char16_t num = '0';
+    if (aNativeKey.mVirtualKeyCode >= VK_NUMPAD0 &&
+        aNativeKey.mVirtualKeyCode <= VK_NUMPAD9) {
+      num = '0' + aNativeKey.mVirtualKeyCode - VK_NUMPAD0;
+    }
+    // Otherwise, let's use fake key value for making never match with
+    // mnemonic.
+    else {
+      switch (aNativeKey.mScanCode) {
+        case 0x0052:  // Numpad0
+          num = '0';
+          break;
+        case 0x004F:  // Numpad1
+          num = '1';
+          break;
+        case 0x0050:  // Numpad2
+          num = '2';
+          break;
+        case 0x0051:  // Numpad3
+          num = '3';
+          break;
+        case 0x004B:  // Numpad4
+          num = '4';
+          break;
+        case 0x004C:  // Numpad5
+          num = '5';
+          break;
+        case 0x004D:  // Numpad6
+          num = '6';
+          break;
+        case 0x0047:  // Numpad7
+          num = '7';
+          break;
+        case 0x0048:  // Numpad8
+          num = '8';
+          break;
+        case 0x0049:  // Numpad9
+          num = '9';
+          break;
+        default:
+          MOZ_ASSERT_UNREACHABLE(
+              "IsTypingUnicodeScalarValue() must have returned true for wrong "
+              "scancode");
+          break;
+      }
+    }
+    aNativeKey.mCommittedCharsAndModifiers.Append(num,
+                                                  aNativeKey.GetModifiers());
+    aNativeKey.mKeyNameIndex = KEY_NAME_INDEX_USE_STRING;
+    return;
+  }
+
+  // When it's followed by non-dead char message(s) for printable character(s),
+  // aNativeKey should dispatch eKeyPress events for them rather than
+  // information from keyboard layout because respecting WM_(SYS)CHAR messages
+  // guarantees that we can always input characters which is expected by
+  // the user even if the user uses odd keyboard layout.
+  // Or, when it was followed by non-dead char message for a printable character
+  // but it's gone at removing the message from the queue, let's treat it
+  // as a key inputting empty string.
+  if (aNativeKey.IsFollowedByPrintableCharOrSysCharMessage() ||
+      aNativeKey.mCharMessageHasGone) {
+    MOZ_ASSERT(!aNativeKey.IsCharMessage(aNativeKey.mMsg));
+    if (aNativeKey.IsFollowedByPrintableCharOrSysCharMessage()) {
+      // Initialize mCommittedCharsAndModifiers with following char messages.
+      aNativeKey.InitCommittedCharsAndModifiersWithFollowingCharMessages();
+      MOZ_ASSERT(!aNativeKey.mCommittedCharsAndModifiers.IsEmpty());
+
+      // Currently, we are doing a ugly hack to keypress events to cause
+      // inputting character even if Ctrl or Alt key is pressed, that is, we
+      // remove Ctrl and Alt modifier state from keypress event.  However, for
+      // example, Ctrl+Space which causes ' ' of WM_CHAR message never causes
+      // keypress event whose ctrlKey is true.  For preventing this problem,
+      // we should mark as not removable if Ctrl or Alt key does not cause
+      // changing inputting character.
+      if (IsPrintableCharKey(aNativeKey.mOriginalVirtualKeyCode) &&
+          (aNativeKey.IsControl() ^ aNativeKey.IsAlt())) {
+        ModifierKeyState state = aNativeKey.ModifierKeyStateRef();
+        state.Unset(MODIFIER_ALT | MODIFIER_CONTROL);
+        UniCharsAndModifiers charsWithoutModifier =
+            GetUniCharsAndModifiers(aNativeKey.GenericVirtualKeyCode(), state);
+        aNativeKey.mCanIgnoreModifierStateAtKeyPress =
+            !charsWithoutModifier.UniCharsEqual(
+                aNativeKey.mCommittedCharsAndModifiers);
+      }
+    } else {
+      aNativeKey.mCommittedCharsAndModifiers.Clear();
+    }
+    aNativeKey.mKeyNameIndex = KEY_NAME_INDEX_USE_STRING;
+
+    // If it's not in dead key sequence, we don't need to do anymore here.
+    if (!IsInDeadKeySequence()) {
+      return;
+    }
+
+    // If it's in dead key sequence and dead char is inputted as is, we need to
+    // set the previous modifier state which is stored when preceding dead key
+    // is pressed.
+    UniCharsAndModifiers deadChars = GetDeadUniCharsAndModifiers();
+    aNativeKey.mCommittedCharsAndModifiers.OverwriteModifiersIfBeginsWith(
+        deadChars);
+    // Finish the dead key sequence.
+    DeactivateDeadKeyState();
+    return;
+  }
+
+  // If it's a dead key, aNativeKey will be initialized by
+  // MaybeInitNativeKeyAsDeadKey().
+  if (MaybeInitNativeKeyAsDeadKey(aNativeKey)) {
+    return;
+  }
+
+  // If the key is not a usual printable key, KeyboardLayout class assume that
+  // it's not cause dead char nor printable char.  Therefore, there are nothing
+  // to do here fore such keys (e.g., function keys).
+  // However, this should keep dead key state even if non-printable key is
+  // pressed during a dead key sequence.
+  if (!IsPrintableCharKey(aNativeKey.mOriginalVirtualKeyCode)) {
+    return;
+  }
+
+  MOZ_ASSERT(aNativeKey.mOriginalVirtualKeyCode != VK_PACKET,
+             "At handling VK_PACKET, we shouldn't refer keyboard layout");
+  MOZ_ASSERT(
+      aNativeKey.mKeyNameIndex == KEY_NAME_INDEX_USE_STRING,
+      "Printable key's key name index must be KEY_NAME_INDEX_USE_STRING");
+
+  // If it's in dead key handling and the pressed key causes a composite
+  // character, aNativeKey will be initialized by
+  // MaybeInitNativeKeyWithCompositeChar().
+  if (MaybeInitNativeKeyWithCompositeChar(aNativeKey)) {
+    return;
+  }
+
+  UniCharsAndModifiers baseChars = GetUniCharsAndModifiers(aNativeKey);
+
+  // If the key press isn't related to any dead keys, initialize aNativeKey
+  // with the characters which should be caused by the key.
+  if (!IsInDeadKeySequence()) {
+    aNativeKey.mCommittedCharsAndModifiers = baseChars;
+    return;
+  }
+
+  // If the key doesn't cause a composite character with preceding dead key,
+  // initialize aNativeKey with the dead-key character followed by current
+  // key's character.
+  UniCharsAndModifiers deadChars = GetDeadUniCharsAndModifiers();
+  aNativeKey.mCommittedCharsAndModifiers = deadChars + baseChars;
+  if (aNativeKey.IsKeyDownMessage()) {
+    DeactivateDeadKeyState();
+  }
+}
+
+bool KeyboardLayout::MaybeInitNativeKeyAsDeadKey(NativeKey& aNativeKey) {
+  // Only when it's not in dead key sequence, we can trust IsDeadKey() result.
+  if (!IsInDeadKeySequence() && !IsDeadKey(aNativeKey)) {
+    return false;
+  }
+
+  // When keydown message is followed by a dead char message, it should be
+  // initialized as dead key.
+  bool isDeadKeyDownEvent =
+      aNativeKey.IsKeyDownMessage() && aNativeKey.IsFollowedByDeadCharMessage();
+
+  // When keyup message is received, let's check if it's one of preceding
+  // dead keys because keydown message order and keyup message order may be
+  // different.
+  bool isDeadKeyUpEvent =
+      !aNativeKey.IsKeyDownMessage() &&
+      mActiveDeadKeys.Contains(aNativeKey.GenericVirtualKeyCode());
+
+  if (isDeadKeyDownEvent || isDeadKeyUpEvent) {
+    ActivateDeadKeyState(aNativeKey);
+    // Any dead key events don't generate characters.  So, a dead key should
+    // cause only keydown event and keyup event whose KeyboardEvent.key
+    // values are "Dead".
+    aNativeKey.mCommittedCharsAndModifiers.Clear();
+    aNativeKey.mKeyNameIndex = KEY_NAME_INDEX_Dead;
+    return true;
+  }
+
+  // At keydown message handling, we need to forget the first dead key
+  // because there is no guarantee coming WM_KEYUP for the second dead
+  // key before next WM_KEYDOWN.  E.g., due to auto key repeat or pressing
+  // another dead key before releasing current key.  Therefore, we can
+  // set only a character for current key for keyup event.
+  if (!IsInDeadKeySequence()) {
+    aNativeKey.mCommittedCharsAndModifiers =
+        GetUniCharsAndModifiers(aNativeKey);
+    return true;
+  }
+
+  // When non-printable key event comes during a dead key sequence, that must
+  // be a modifier key event.  So, such events shouldn't be handled as a part
+  // of the dead key sequence.
+  if (!IsDeadKey(aNativeKey)) {
+    return false;
+  }
+
+  // FYI: Following code may run when the user doesn't input text actually
+  //      but the key sequence is a dead key sequence.  For example,
+  //      ` -> Ctrl+` with Spanish keyboard layout.  Let's keep using this
+  //      complicated code for now because this runs really rarely.
+
+  // Dead key followed by another dead key may cause a composed character
+  // (e.g., "Russian - Mnemonic" keyboard layout's 's' -> 'c').
+  if (MaybeInitNativeKeyWithCompositeChar(aNativeKey)) {
+    return true;
+  }
+
+  // Otherwise, dead key followed by another dead key causes inputting both
+  // character.
+  UniCharsAndModifiers prevDeadChars = GetDeadUniCharsAndModifiers();
+  UniCharsAndModifiers newChars = GetUniCharsAndModifiers(aNativeKey);
+  // But keypress events should be fired for each committed character.
+  aNativeKey.mCommittedCharsAndModifiers = prevDeadChars + newChars;
+  if (aNativeKey.IsKeyDownMessage()) {
+    DeactivateDeadKeyState();
+  }
+  return true;
+}
+
+bool KeyboardLayout::MaybeInitNativeKeyWithCompositeChar(
+    NativeKey& aNativeKey) {
+  if (!IsInDeadKeySequence()) {
+    return false;
+  }
+
+  if (NS_WARN_IF(!IsPrintableCharKey(aNativeKey.mOriginalVirtualKeyCode))) {
+    return false;
+  }
+
+  UniCharsAndModifiers baseChars = GetUniCharsAndModifiers(aNativeKey);
+  if (baseChars.IsEmpty() || !baseChars.CharAt(0)) {
+    return false;
+  }
+
+  char16_t compositeChar = GetCompositeChar(baseChars.CharAt(0));
+  if (!compositeChar) {
+    return false;
+  }
+
+  // Active dead-key and base character does produce exactly one composite
+  // character.
+  aNativeKey.mCommittedCharsAndModifiers.Append(compositeChar,
+                                                baseChars.ModifiersAt(0));
+  if (aNativeKey.IsKeyDownMessage()) {
+    DeactivateDeadKeyState();
+  }
+  return true;
+}
+
+UniCharsAndModifiers KeyboardLayout::GetUniCharsAndModifiers(
+    uint8_t aVirtualKey, VirtualKey::ShiftState aShiftState) const {
+  UniCharsAndModifiers result;
+  int32_t key = GetKeyIndex(aVirtualKey);
+  if (key < 0) {
+    return result;
+  }
+  return mVirtualKeys[key].GetUniChars(aShiftState);
+}
+
+UniCharsAndModifiers KeyboardLayout::GetDeadUniCharsAndModifiers() const {
+  MOZ_RELEASE_ASSERT(mActiveDeadKeys.Length() == mDeadKeyShiftStates.Length());
+
+  if (NS_WARN_IF(mActiveDeadKeys.IsEmpty())) {
+    return UniCharsAndModifiers();
+  }
+
+  UniCharsAndModifiers result;
+  for (size_t i = 0; i < mActiveDeadKeys.Length(); ++i) {
+    result +=
+        GetUniCharsAndModifiers(mActiveDeadKeys[i], mDeadKeyShiftStates[i]);
+  }
+  return result;
+}
+
+char16_t KeyboardLayout::GetCompositeChar(char16_t aBaseChar) const {
+  if (NS_WARN_IF(mActiveDeadKeys.IsEmpty())) {
+    return 0;
+  }
+  // XXX Currently, we don't support computing a composite character with
+  //     two or more dead keys since it needs big table for supporting
+  //     long chained dead keys.  However, this should be a minor bug
+  //     because this runs only when the latest keydown event does not cause
+  //     WM_(SYS)CHAR messages.  So, when user wants to input a character,
+  //     this path never runs.
+  if (mActiveDeadKeys.Length() > 1) {
+    return 0;
+  }
+  int32_t key = GetKeyIndex(mActiveDeadKeys[0]);
+  if (key < 0) {
+    return 0;
+  }
+  return mVirtualKeys[key].GetCompositeChar(mDeadKeyShiftStates[0], aBaseChar);
+}
+
+static bool IsValidKeyboardLayoutsChild(const nsAString& aChildName) {
+  if (aChildName.Length() != 8) {
+    return false;
+  }
+  for (size_t i = 0; i < aChildName.Length(); i++) {
+    if ((aChildName[i] >= '0' && aChildName[i] <= '9') ||
+        (aChildName[i] >= 'a' && aChildName[i] <= 'f') ||
+        (aChildName[i] >= 'A' && aChildName[i] <= 'F')) {
+      continue;
+    }
+    return false;
+  }
+  return true;
+}
+
+// static
+nsCString KeyboardLayout::GetLayoutName(HKL aLayout) {
+  constexpr auto kKeyboardLayouts =
+      u"SYSTEM\\CurrentControlSet\\Control\\Keyboard Layouts\\"_ns;
+  uint16_t language = reinterpret_cast<uintptr_t>(aLayout) & 0xFFFF;
+  uint16_t layout = (reinterpret_cast<uintptr_t>(aLayout) >> 16) & 0xFFFF;
+  // If the layout is less than 0xA000XXXX (normal keyboard layout for the
+  // language) or 0xEYYYXXXX (IMM-IME), we can retrieve its name simply.
+  if (layout < 0xA000 || (layout & 0xF000) == 0xE000) {
+    nsAutoString key(kKeyboardLayouts);
+    key.AppendPrintf("%08" PRIXPTR, layout < 0xA000
+                                        ? layout
+                                        : reinterpret_cast<uintptr_t>(aLayout));
+    wchar_t buf[256];
+    if (NS_WARN_IF(!WinRegistry::GetString(
+            HKEY_LOCAL_MACHINE, key, u"Layout Text"_ns, buf,
+            WinRegistry::kLegacyWinUtilsStringFlags))) {
+      return "No name or too long name"_ns;
+    }
+    return NS_ConvertUTF16toUTF8(buf);
+  }
+
+  if (NS_WARN_IF((layout & 0xF000) != 0xF000)) {
+    nsCString result;
+    result.AppendPrintf("Odd HKL: 0x%08" PRIXPTR,
+                        reinterpret_cast<uintptr_t>(aLayout));
+    return result;
+  }
+
+  // Otherwise, we need to walk the registry under "Keyboard Layouts".
+  WinRegistry::Key regKey(HKEY_LOCAL_MACHINE, kKeyboardLayouts,
+                          WinRegistry::KeyMode::Read);
+  if (NS_WARN_IF(!regKey)) {
+    return ""_ns;
+  }
+  uint32_t childCount = regKey.GetChildCount();
+  if (NS_WARN_IF(!childCount)) {
+    return ""_ns;
+  }
+  for (uint32_t i = 0; i < childCount; i++) {
+    nsAutoString childName;
+    if (NS_WARN_IF(!regKey.GetChildName(i, childName)) ||
+        !IsValidKeyboardLayoutsChild(childName)) {
+      continue;
+    }
+    nsresult rv = NS_OK;
+    uint32_t childNum = static_cast<uint32_t>(childName.ToInteger64(&rv, 16));
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      continue;
+    }
+    // Ignore normal keyboard layouts for each language.
+    if (childNum <= 0xFFFF) {
+      continue;
+    }
+    // If it doesn't start with 'A' nor 'a', language should be matched.
+    if ((childNum & 0xFFFF) != language &&
+        (childNum & 0xF0000000) != 0xA0000000) {
+      continue;
+    }
+    // Then, the child should have "Layout Id" which is "YYY" of 0xFYYYXXXX.
+    nsAutoString key(kKeyboardLayouts);
+    key += childName;
+    WinRegistry::Key regKey(HKEY_LOCAL_MACHINE, key,
+                            WinRegistry::KeyMode::QueryValue);
+    if (NS_WARN_IF(!regKey)) {
+      continue;
+    }
+    wchar_t buf[256];
+    if (NS_WARN_IF(!regKey.GetValueAsString(
+            u"Layout Id"_ns, buf, WinRegistry::kLegacyWinUtilsStringFlags))) {
+      continue;
+    }
+    uint16_t layoutId = wcstol(buf, nullptr, 16);
+    if (layoutId != (layout & 0x0FFF)) {
+      continue;
+    }
+    if (NS_WARN_IF(!regKey.GetValueAsString(
+            u"Layout Text"_ns, buf, WinRegistry::kLegacyWinUtilsStringFlags))) {
+      continue;
+    }
+    return NS_ConvertUTF16toUTF8(buf);
+  }
+  return ""_ns;
+}
+
+void KeyboardLayout::LoadLayout(HKL aLayout) {
+  mIsPendingToRestoreKeyboardLayout = false;
+
+  if (mKeyboardLayout == aLayout) {
+    return;
+  }
+
+  mKeyboardLayout = aLayout;
+  mHasAltGr = false;
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("KeyboardLayout::LoadLayout(aLayout=0x%p (%s))", aLayout,
+           GetLayoutName(aLayout).get()));
+
+  BYTE kbdState[256];
+  memset(kbdState, 0, sizeof(kbdState));
+
+  BYTE originalKbdState[256];
+  // Bitfield with all shift states that have at least one dead-key.
+  uint16_t shiftStatesWithDeadKeys = 0;
+  // Bitfield with all shift states that produce any possible dead-key base
+  // characters.
+  uint16_t shiftStatesWithBaseChars = 0;
+
+  mActiveDeadKeys.Clear();
+  mDeadKeyShiftStates.Clear();
+
+  ReleaseDeadKeyTables();
+
+  ::GetKeyboardState(originalKbdState);
+
+  // For each shift state gather all printable characters that are produced
+  // for normal case when no any dead-key is active.
+
+  for (VirtualKey::ShiftState shiftState = 0; shiftState < 16; shiftState++) {
+    VirtualKey::FillKbdState(kbdState, shiftState);
+    bool isAltGr = VirtualKey::IsAltGrIndex(shiftState);
+    for (uint32_t virtualKey = 0; virtualKey < 256; virtualKey++) {
+      int32_t vki = GetKeyIndex(virtualKey);
+      if (vki < 0) {
+        continue;
+      }
+      NS_ASSERTION(uint32_t(vki) < ArrayLength(mVirtualKeys), "invalid index");
+      char16_t uniChars[5];
+      int32_t ret = ::ToUnicodeEx(virtualKey, 0, kbdState, (LPWSTR)uniChars,
+                                  ArrayLength(uniChars), 0, mKeyboardLayout);
+      // dead-key
+      if (ret < 0) {
+        shiftStatesWithDeadKeys |= (1 << shiftState);
+        // Repeat dead-key to deactivate it and get its character
+        // representation.
+        char16_t deadChar[2];
+        ret = ::ToUnicodeEx(virtualKey, 0, kbdState, (LPWSTR)deadChar,
+                            ArrayLength(deadChar), 0, mKeyboardLayout);
+        NS_ASSERTION(ret == 2, "Expecting twice repeated dead-key character");
+        mVirtualKeys[vki].SetDeadChar(shiftState, deadChar[0]);
+
+        MOZ_LOG(gKeyLog, LogLevel::Verbose,
+                ("  %s (%d): DeadChar(%s, %s) (ret=%d)",
+                 kVirtualKeyName[virtualKey], vki,
+                 GetShiftStateName(shiftState).get(),
+                 GetCharacterCodeNames(deadChar, 1).get(), ret));
+      } else {
+        if (ret == 1) {
+          // dead-key can pair only with exactly one base character.
+          shiftStatesWithBaseChars |= (1 << shiftState);
+        }
+        mVirtualKeys[vki].SetNormalChars(shiftState, uniChars, ret);
+        MOZ_LOG(gKeyLog, LogLevel::Verbose,
+                ("  %s (%d): NormalChar(%s, %s) (ret=%d)",
+                 kVirtualKeyName[virtualKey], vki,
+                 GetShiftStateName(shiftState).get(),
+                 GetCharacterCodeNames(uniChars, ret).get(), ret));
+      }
+
+      // If the key inputs at least one character with AltGr modifier,
+      // check if AltGr changes inputting character.  If it does, mark
+      // this keyboard layout has AltGr modifier actually.
+      if (!mHasAltGr && ret > 0 && isAltGr &&
+          mVirtualKeys[vki].IsChangedByAltGr(shiftState)) {
+        mHasAltGr = true;
+        MOZ_LOG(gKeyLog, LogLevel::Info,
+                ("  Found a key (%s) changed by AltGr: %s -> %s (%s) (ret=%d)",
+                 kVirtualKeyName[virtualKey],
+                 GetCharacterCodeNames(
+                     mVirtualKeys[vki].GetNativeUniChars(
+                         shiftState - VirtualKey::ShiftStateIndex::eAltGr))
+                     .get(),
+                 GetCharacterCodeNames(
+                     mVirtualKeys[vki].GetNativeUniChars(shiftState))
+                     .get(),
+                 GetShiftStateName(shiftState).get(), ret));
+      }
+    }
+  }
+
+  // Now process each dead-key to find all its base characters and resulting
+  // composite characters.
+  for (VirtualKey::ShiftState shiftState = 0; shiftState < 16; shiftState++) {
+    if (!(shiftStatesWithDeadKeys & (1 << shiftState))) {
+      continue;
+    }
+
+    VirtualKey::FillKbdState(kbdState, shiftState);
+
+    for (uint32_t virtualKey = 0; virtualKey < 256; virtualKey++) {
+      int32_t vki = GetKeyIndex(virtualKey);
+      if (vki >= 0 && mVirtualKeys[vki].IsDeadKey(shiftState)) {
+        AutoTArray<DeadKeyEntry, 256> deadKeyArray;
+        uint32_t n = GetDeadKeyCombinations(
+            virtualKey, kbdState, shiftStatesWithBaseChars, deadKeyArray);
+        const DeadKeyTable* dkt =
+            mVirtualKeys[vki].MatchingDeadKeyTable(deadKeyArray.Elements(), n);
+        if (!dkt) {
+          dkt = AddDeadKeyTable(deadKeyArray.Elements(), n);
+        }
+        mVirtualKeys[vki].AttachDeadKeyTable(shiftState, dkt);
+      }
+    }
+  }
+
+  ::SetKeyboardState(originalKbdState);
+
+  if (MOZ_LOG_TEST(gKeyLog, LogLevel::Verbose)) {
+    static const UINT kExtendedScanCode[] = {0x0000, 0xE000};
+    static const UINT kMapType = MAPVK_VSC_TO_VK_EX;
+    MOZ_LOG(gKeyLog, LogLevel::Verbose,
+            ("Logging virtual keycode values for scancode (0x%p)...",
+             mKeyboardLayout));
+    for (uint32_t i = 0; i < ArrayLength(kExtendedScanCode); i++) {
+      for (uint32_t j = 1; j <= 0xFF; j++) {
+        UINT scanCode = kExtendedScanCode[i] + j;
+        UINT virtualKeyCode =
+            ::MapVirtualKeyEx(scanCode, kMapType, mKeyboardLayout);
+        MOZ_LOG(gKeyLog, LogLevel::Verbose,
+                ("0x%04X, %s", scanCode, kVirtualKeyName[virtualKeyCode]));
+      }
+    }
+  }
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("  AltGr key is %s in %s", mHasAltGr ? "found" : "not found",
+           GetLayoutName(aLayout).get()));
+}
+
+inline int32_t KeyboardLayout::GetKeyIndex(uint8_t aVirtualKey) {
+  // Currently these 68 (NS_NUM_OF_KEYS) virtual keys are assumed
+  // to produce visible representation:
+  // 0x20 - VK_SPACE          ' '
+  // 0x30..0x39               '0'..'9'
+  // 0x41..0x5A               'A'..'Z'
+  // 0x60..0x69               '0'..'9' on numpad
+  // 0x6A - VK_MULTIPLY       '*' on numpad
+  // 0x6B - VK_ADD            '+' on numpad
+  // 0x6D - VK_SUBTRACT       '-' on numpad
+  // 0x6E - VK_DECIMAL        '.' on numpad
+  // 0x6F - VK_DIVIDE         '/' on numpad
+  // 0x6E - VK_DECIMAL        '.'
+  // 0xBA - VK_OEM_1          ';:' for US
+  // 0xBB - VK_OEM_PLUS       '+' any country
+  // 0xBC - VK_OEM_COMMA      ',' any country
+  // 0xBD - VK_OEM_MINUS      '-' any country
+  // 0xBE - VK_OEM_PERIOD     '.' any country
+  // 0xBF - VK_OEM_2          '/?' for US
+  // 0xC0 - VK_OEM_3          '`~' for US
+  // 0xC1 - VK_ABNT_C1        '/?' for Brazilian
+  // 0xC2 - VK_ABNT_C2        separator key on numpad (Brazilian or JIS for Mac)
+  // 0xDB - VK_OEM_4          '[{' for US
+  // 0xDC - VK_OEM_5          '\|' for US
+  // 0xDD - VK_OEM_6          ']}' for US
+  // 0xDE - VK_OEM_7          ''"' for US
+  // 0xDF - VK_OEM_8
+  // 0xE1 - no name
+  // 0xE2 - VK_OEM_102        '\_' for JIS
+  // 0xE3 - no name
+  // 0xE4 - no name
+
+  static const int8_t xlat[256] = {
+      // 0   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F
+      //-----------------------------------------------------------------------
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  // 00
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  // 10
+      0,  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  // 20
+      1,  2,  3,  4,  5,  6,  7,  8,  9,  10, -1, -1, -1, -1, -1, -1,  // 30
+      -1, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,  // 40
+      26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, -1, -1, -1, -1, -1,  // 50
+      37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, -1, 49, 50, 51,  // 60
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  // 70
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  // 80
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  // 90
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  // A0
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 52, 53, 54, 55, 56, 57,  // B0
+      58, 59, 60, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  // C0
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 61, 62, 63, 64, 65,  // D0
+      -1, 66, 67, 68, 69, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  // E0
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1   // F0
+  };
+
+  return xlat[aVirtualKey];
+}
+
+const DeadKeyTable* KeyboardLayout::AddDeadKeyTable(
+    const DeadKeyEntry* aDeadKeyArray, uint32_t aEntries) {
+  DeadKeyTableListEntry* next = mDeadKeyTableListHead;
+
+  const size_t bytes = offsetof(DeadKeyTableListEntry, data) +
+                       DeadKeyTable::SizeInBytes(aEntries);
+  uint8_t* p = new uint8_t[bytes];
+
+  mDeadKeyTableListHead = reinterpret_cast<DeadKeyTableListEntry*>(p);
+  mDeadKeyTableListHead->next = next;
+
+  DeadKeyTable* dkt =
+      reinterpret_cast<DeadKeyTable*>(mDeadKeyTableListHead->data);
+
+  dkt->Init(aDeadKeyArray, aEntries);
+
+  return dkt;
+}
+
+void KeyboardLayout::ReleaseDeadKeyTables() {
+  while (mDeadKeyTableListHead) {
+    uint8_t* p = reinterpret_cast<uint8_t*>(mDeadKeyTableListHead);
+    mDeadKeyTableListHead = mDeadKeyTableListHead->next;
+
+    delete[] p;
+  }
+}
+
+bool KeyboardLayout::EnsureDeadKeyActive(bool aIsActive, uint8_t aDeadKey,
+                                         const PBYTE aDeadKeyKbdState) {
+  int32_t ret;
+  do {
+    char16_t dummyChars[5];
+    ret =
+        ::ToUnicodeEx(aDeadKey, 0, (PBYTE)aDeadKeyKbdState, (LPWSTR)dummyChars,
+                      ArrayLength(dummyChars), 0, mKeyboardLayout);
+    // returned values:
+    // <0 - Dead key state is active. The keyboard driver will wait for next
+    //      character.
+    //  1 - Previous pressed key was a valid base character that produced
+    //      exactly one composite character.
+    // >1 - Previous pressed key does not produce any composite characters.
+    //      Return dead-key character followed by base character(s).
+  } while ((ret < 0) != aIsActive);
+
+  return (ret < 0);
+}
+
+void KeyboardLayout::ActivateDeadKeyState(const NativeKey& aNativeKey) {
+  // Dead-key state should be activated at keydown.
+  if (!aNativeKey.IsKeyDownMessage()) {
+    return;
+  }
+
+  mActiveDeadKeys.AppendElement(aNativeKey.mOriginalVirtualKeyCode);
+  mDeadKeyShiftStates.AppendElement(aNativeKey.GetShiftState());
+}
+
+void KeyboardLayout::DeactivateDeadKeyState() {
+  if (mActiveDeadKeys.IsEmpty()) {
+    return;
+  }
+
+  BYTE kbdState[256];
+  memset(kbdState, 0, sizeof(kbdState));
+
+  // Assume that the last dead key can finish dead key sequence.
+  VirtualKey::FillKbdState(kbdState, mDeadKeyShiftStates.LastElement());
+  EnsureDeadKeyActive(false, mActiveDeadKeys.LastElement(), kbdState);
+  mActiveDeadKeys.Clear();
+  mDeadKeyShiftStates.Clear();
+}
+
+bool KeyboardLayout::AddDeadKeyEntry(char16_t aBaseChar,
+                                     char16_t aCompositeChar,
+                                     nsTArray<DeadKeyEntry>& aDeadKeyArray) {
+  auto dke = DeadKeyEntry(aBaseChar, aCompositeChar);
+  for (uint32_t index = 0; index < aDeadKeyArray.Length(); index++) {
+    if (aDeadKeyArray[index] == dke) {
+      return false;
+    }
+  }
+
+  aDeadKeyArray.AppendElement(dke);
+
+  return true;
+}
+
+uint32_t KeyboardLayout::GetDeadKeyCombinations(
+    uint8_t aDeadKey, const PBYTE aDeadKeyKbdState,
+    uint16_t aShiftStatesWithBaseChars, nsTArray<DeadKeyEntry>& aDeadKeyArray) {
+  bool deadKeyActive = false;
+  uint32_t entries = 0;
+  BYTE kbdState[256];
+  memset(kbdState, 0, sizeof(kbdState));
+
+  for (uint32_t shiftState = 0; shiftState < 16; shiftState++) {
+    if (!(aShiftStatesWithBaseChars & (1 << shiftState))) {
+      continue;
+    }
+
+    VirtualKey::FillKbdState(kbdState, shiftState);
+
+    for (uint32_t virtualKey = 0; virtualKey < 256; virtualKey++) {
+      int32_t vki = GetKeyIndex(virtualKey);
+      // Dead-key can pair only with such key that produces exactly one base
+      // character.
+      if (vki >= 0 &&
+          mVirtualKeys[vki].GetNativeUniChars(shiftState).Length() == 1) {
+        // Ensure dead-key is in active state, when it swallows entered
+        // character and waits for the next pressed key.
+        if (!deadKeyActive) {
+          deadKeyActive = EnsureDeadKeyActive(true, aDeadKey, aDeadKeyKbdState);
+        }
+
+        // Depending on the character the followed the dead-key, the keyboard
+        // driver can produce one composite character, or a dead-key character
+        // followed by a second character.
+        char16_t compositeChars[5];
+        int32_t ret =
+            ::ToUnicodeEx(virtualKey, 0, kbdState, (LPWSTR)compositeChars,
+                          ArrayLength(compositeChars), 0, mKeyboardLayout);
+        switch (ret) {
+          case 0:
+            // This key combination does not produce any characters. The
+            // dead-key is still in active state.
+            break;
+          case 1: {
+            char16_t baseChars[5];
+            ret = ::ToUnicodeEx(virtualKey, 0, kbdState, (LPWSTR)baseChars,
+                                ArrayLength(baseChars), 0, mKeyboardLayout);
+            if (entries < aDeadKeyArray.Capacity()) {
+              switch (ret) {
+                case 1:
+                  // Exactly one composite character produced. Now, when
+                  // dead-key is not active, repeat the last character one more
+                  // time to determine the base character.
+                  if (AddDeadKeyEntry(baseChars[0], compositeChars[0],
+                                      aDeadKeyArray)) {
+                    entries++;
+                  }
+                  deadKeyActive = false;
+                  break;
+                case -1: {
+                  // If pressing another dead-key produces different character,
+                  // we should register the dead-key entry with first character
+                  // produced by current key.
+
+                  // First inactivate the dead-key state completely.
+                  deadKeyActive =
+                      EnsureDeadKeyActive(false, aDeadKey, aDeadKeyKbdState);
+                  if (NS_WARN_IF(deadKeyActive)) {
+                    MOZ_LOG(gKeyLog, LogLevel::Error,
+                            ("  failed to deactivating the dead-key state..."));
+                    break;
+                  }
+                  for (int32_t i = 0; i < 5; ++i) {
+                    ret = ::ToUnicodeEx(
+                        virtualKey, 0, kbdState, (LPWSTR)baseChars,
+                        ArrayLength(baseChars), 0, mKeyboardLayout);
+                    if (ret >= 0) {
+                      break;
+                    }
+                  }
+                  if (ret > 0 &&
+                      AddDeadKeyEntry(baseChars[0], compositeChars[0],
+                                      aDeadKeyArray)) {
+                    entries++;
+                  }
+                  // Inactivate dead-key state for current virtual keycode.
+                  EnsureDeadKeyActive(false, virtualKey, kbdState);
+                  break;
+                }
+                default:
+                  NS_WARNING("File a bug for this dead-key handling!");
+                  deadKeyActive = false;
+                  break;
+              }
+            }
+            MOZ_LOG(
+                gKeyLog, LogLevel::Verbose,
+                ("  %s -> %s (%d): DeadKeyEntry(%s, %s) (ret=%d)",
+                 kVirtualKeyName[aDeadKey], kVirtualKeyName[virtualKey], vki,
+                 GetCharacterCodeNames(compositeChars, 1).get(),
+                 ret <= 0
+                     ? "''"
+                     : GetCharacterCodeNames(baseChars, std::min(ret, 5)).get(),
+                 ret));
+            break;
+          }
+          default:
+            // 1. Unexpected dead-key. Dead-key chaining is not supported.
+            // 2. More than one character generated. This is not a valid
+            //    dead-key and base character combination.
+            deadKeyActive = false;
+            MOZ_LOG(
+                gKeyLog, LogLevel::Verbose,
+                ("  %s -> %s (%d): Unsupport dead key type(%s) (ret=%d)",
+                 kVirtualKeyName[aDeadKey], kVirtualKeyName[virtualKey], vki,
+                 ret <= 0
+                     ? "''"
+                     : GetCharacterCodeNames(compositeChars, std::min(ret, 5))
+                           .get(),
+                 ret));
+            break;
+        }
+      }
+    }
+  }
+
+  if (deadKeyActive) {
+    deadKeyActive = EnsureDeadKeyActive(false, aDeadKey, aDeadKeyKbdState);
+  }
+
+  aDeadKeyArray.Sort();
+
+  return entries;
+}
+
+uint32_t KeyboardLayout::ConvertNativeKeyCodeToDOMKeyCode(
+    UINT aNativeKeyCode) const {
+  // Alphabet or Numeric or Numpad or Function keys
+  if ((aNativeKeyCode >= 0x30 && aNativeKeyCode <= 0x39) ||
+      (aNativeKeyCode >= 0x41 && aNativeKeyCode <= 0x5A) ||
+      (aNativeKeyCode >= 0x60 && aNativeKeyCode <= 0x87)) {
+    return static_cast<uint32_t>(aNativeKeyCode);
+  }
+  switch (aNativeKeyCode) {
+    // Following keycodes are same as our DOM keycodes
+    case VK_CANCEL:
+    case VK_BACK:
+    case VK_TAB:
+    case VK_CLEAR:
+    case VK_RETURN:
+    case VK_SHIFT:
+    case VK_CONTROL:
+    case VK_MENU:  // Alt
+    case VK_PAUSE:
+    case VK_CAPITAL:  // CAPS LOCK
+    case VK_KANA:     // same as VK_HANGUL
+    case VK_JUNJA:
+    case VK_FINAL:
+    case VK_HANJA:  // same as VK_KANJI
+    case VK_ESCAPE:
+    case VK_CONVERT:
+    case VK_NONCONVERT:
+    case VK_ACCEPT:
+    case VK_MODECHANGE:
+    case VK_SPACE:
+    case VK_PRIOR:  // PAGE UP
+    case VK_NEXT:   // PAGE DOWN
+    case VK_END:
+    case VK_HOME:
+    case VK_LEFT:
+    case VK_UP:
+    case VK_RIGHT:
+    case VK_DOWN:
+    case VK_SELECT:
+    case VK_PRINT:
+    case VK_EXECUTE:
+    case VK_SNAPSHOT:
+    case VK_INSERT:
+    case VK_DELETE:
+    case VK_APPS:  // Context Menu
+    case VK_SLEEP:
+    case VK_NUMLOCK:
+    case VK_SCROLL:  // SCROLL LOCK
+    case VK_ATTN:    // Attension key of IBM midrange computers, e.g., AS/400
+    case VK_CRSEL:   // Cursor Selection
+    case VK_EXSEL:   // Extend Selection
+    case VK_EREOF:   // Erase EOF key of IBM 3270 keyboard layout
+    case VK_PLAY:
+    case VK_ZOOM:
+    case VK_PA1:  // PA1 key of IBM 3270 keyboard layout
+      return uint32_t(aNativeKeyCode);
+
+    case VK_HELP:
+      return NS_VK_HELP;
+
+    // Windows key should be mapped to a Win keycode
+    // They should be able to be distinguished by DOM3 KeyboardEvent.location
+    case VK_LWIN:
+    case VK_RWIN:
+      return NS_VK_WIN;
+
+    case VK_VOLUME_MUTE:
+      return NS_VK_VOLUME_MUTE;
+    case VK_VOLUME_DOWN:
+      return NS_VK_VOLUME_DOWN;
+    case VK_VOLUME_UP:
+      return NS_VK_VOLUME_UP;
+
+    case VK_LSHIFT:
+    case VK_RSHIFT:
+      return NS_VK_SHIFT;
+
+    case VK_LCONTROL:
+    case VK_RCONTROL:
+      return NS_VK_CONTROL;
+
+    // Note that even if the key is AltGr, we should return NS_VK_ALT for
+    // compatibility with both older Gecko and the other browsers.
+    case VK_LMENU:
+    case VK_RMENU:
+      return NS_VK_ALT;
+
+    // Following keycodes are not defined in our DOM keycodes.
+    case VK_BROWSER_BACK:
+    case VK_BROWSER_FORWARD:
+    case VK_BROWSER_REFRESH:
+    case VK_BROWSER_STOP:
+    case VK_BROWSER_SEARCH:
+    case VK_BROWSER_FAVORITES:
+    case VK_BROWSER_HOME:
+    case VK_MEDIA_NEXT_TRACK:
+    case VK_MEDIA_PREV_TRACK:
+    case VK_MEDIA_STOP:
+    case VK_MEDIA_PLAY_PAUSE:
+    case VK_LAUNCH_MAIL:
+    case VK_LAUNCH_MEDIA_SELECT:
+    case VK_LAUNCH_APP1:
+    case VK_LAUNCH_APP2:
+      return 0;
+
+    // Following OEM specific virtual keycodes should pass through DOM keyCode
+    // for compatibility with the other browsers on Windows.
+
+    // Following OEM specific virtual keycodes are defined for Fujitsu/OASYS.
+    case VK_OEM_FJ_JISHO:
+    case VK_OEM_FJ_MASSHOU:
+    case VK_OEM_FJ_TOUROKU:
+    case VK_OEM_FJ_LOYA:
+    case VK_OEM_FJ_ROYA:
+    // Not sure what means "ICO".
+    case VK_ICO_HELP:
+    case VK_ICO_00:
+    case VK_ICO_CLEAR:
+    // Following OEM specific virtual keycodes are defined for Nokia/Ericsson.
+    case VK_OEM_RESET:
+    case VK_OEM_JUMP:
+    case VK_OEM_PA1:
+    case VK_OEM_PA2:
+    case VK_OEM_PA3:
+    case VK_OEM_WSCTRL:
+    case VK_OEM_CUSEL:
+    case VK_OEM_ATTN:
+    case VK_OEM_FINISH:
+    case VK_OEM_COPY:
+    case VK_OEM_AUTO:
+    case VK_OEM_ENLW:
+    case VK_OEM_BACKTAB:
+    // VK_OEM_CLEAR is defined as not OEM specific, but let's pass though
+    // DOM keyCode like other OEM specific virtual keycodes.
+    case VK_OEM_CLEAR:
+      return uint32_t(aNativeKeyCode);
+
+    // 0xE1 is an OEM specific virtual keycode. However, the value is already
+    // used in our DOM keyCode for AltGr on Linux. So, this virtual keycode
+    // cannot pass through DOM keyCode.
+    case 0xE1:
+      return 0;
+
+    // Following keycodes are OEM keys which are keycodes for non-alphabet and
+    // non-numeric keys, we should compute each keycode of them from unshifted
+    // character which is inputted by each key.  But if the unshifted character
+    // is not an ASCII character but shifted character is an ASCII character,
+    // we should refer it.
+    case VK_OEM_1:
+    case VK_OEM_PLUS:
+    case VK_OEM_COMMA:
+    case VK_OEM_MINUS:
+    case VK_OEM_PERIOD:
+    case VK_OEM_2:
+    case VK_OEM_3:
+    case VK_OEM_4:
+    case VK_OEM_5:
+    case VK_OEM_6:
+    case VK_OEM_7:
+    case VK_OEM_8:
+    case VK_OEM_102:
+    case VK_ABNT_C1: {
+      NS_ASSERTION(IsPrintableCharKey(aNativeKeyCode),
+                   "The key must be printable");
+      ModifierKeyState modKeyState(0);
+      UniCharsAndModifiers uniChars =
+          GetUniCharsAndModifiers(aNativeKeyCode, modKeyState);
+      if (uniChars.Length() != 1 || uniChars.CharAt(0) < ' ' ||
+          uniChars.CharAt(0) > 0x7F) {
+        modKeyState.Set(MODIFIER_SHIFT);
+        uniChars = GetUniCharsAndModifiers(aNativeKeyCode, modKeyState);
+        if (uniChars.Length() != 1 || uniChars.CharAt(0) < ' ' ||
+            uniChars.CharAt(0) > 0x7F) {
+          // In this case, we've returned 0 in this case for long time because
+          // we decided that we should avoid setting same keyCode value to 2 or
+          // more keys since active keyboard layout may have a key to input the
+          // punctuation with different key.  However, setting keyCode to 0
+          // makes some web applications which are aware of neither
+          // KeyboardEvent.key nor KeyboardEvent.code not work with Firefox
+          // when user selects non-ASCII capable keyboard layout such as
+          // Russian and Thai layout.  So, let's decide keyCode value with
+          // major keyboard layout's key which causes the OEM keycode.
+          // Actually, this maps same keyCode value to 2 keys on Russian
+          // keyboard layout.  "Period" key causes VK_OEM_PERIOD but inputs
+          // Yu of Cyrillic and "Slash" key causes VK_OEM_2 (same as US
+          // keyboard layout) but inputs "." (period of ASCII).  Therefore,
+          // we return DOM_VK_PERIOD which is same as VK_OEM_PERIOD for
+          // "Period" key.  On the other hand, we use same keyCode value for
+          // "Slash" key too because it inputs ".".
+          CodeNameIndex code;
+          switch (aNativeKeyCode) {
+            case VK_OEM_1:
+              code = CODE_NAME_INDEX_Semicolon;
+              break;
+            case VK_OEM_PLUS:
+              code = CODE_NAME_INDEX_Equal;
+              break;
+            case VK_OEM_COMMA:
+              code = CODE_NAME_INDEX_Comma;
+              break;
+            case VK_OEM_MINUS:
+              code = CODE_NAME_INDEX_Minus;
+              break;
+            case VK_OEM_PERIOD:
+              code = CODE_NAME_INDEX_Period;
+              break;
+            case VK_OEM_2:
+              code = CODE_NAME_INDEX_Slash;
+              break;
+            case VK_OEM_3:
+              code = CODE_NAME_INDEX_Backquote;
+              break;
+            case VK_OEM_4:
+              code = CODE_NAME_INDEX_BracketLeft;
+              break;
+            case VK_OEM_5:
+              code = CODE_NAME_INDEX_Backslash;
+              break;
+            case VK_OEM_6:
+              code = CODE_NAME_INDEX_BracketRight;
+              break;
+            case VK_OEM_7:
+              code = CODE_NAME_INDEX_Quote;
+              break;
+            case VK_OEM_8:
+              // Use keyCode value for "Backquote" key on UK keyboard layout.
+              code = CODE_NAME_INDEX_Backquote;
+              break;
+            case VK_OEM_102:
+              // Use keyCode value for "IntlBackslash" key.
+              code = CODE_NAME_INDEX_IntlBackslash;
+              break;
+            case VK_ABNT_C1:  // "/" of ABNT.
+              // Use keyCode value for "IntlBackslash" key on ABNT keyboard
+              // layout.
+              code = CODE_NAME_INDEX_IntlBackslash;
+              break;
+            default:
+              MOZ_ASSERT_UNREACHABLE("Handle all OEM keycode values");
+              return 0;
+          }
+          return WidgetKeyboardEvent::GetFallbackKeyCodeOfPunctuationKey(code);
+        }
+      }
+      return WidgetUtils::ComputeKeyCodeFromChar(uniChars.CharAt(0));
+    }
+
+    // IE sets 0xC2 to the DOM keyCode for VK_ABNT_C2.  However, we're already
+    // using NS_VK_SEPARATOR for the separator key on Mac and Linux.  Therefore,
+    // We should keep consistency between Gecko on all platforms rather than
+    // with other browsers since a lot of keyCode values are already different
+    // between browsers.
+    case VK_ABNT_C2:
+      return NS_VK_SEPARATOR;
+
+    // VK_PROCESSKEY means IME already consumed the key event.
+    case VK_PROCESSKEY:
+      return NS_VK_PROCESSKEY;
+    // VK_PACKET is generated by SendInput() API, we don't need to
+    // care this message as key event.
+    case VK_PACKET:
+      return 0;
+    // If a key is not mapped to a virtual keycode, 0xFF is used.
+    case 0xFF:
+      NS_WARNING("The key is failed to be converted to a virtual keycode");
+      return 0;
+  }
+#ifdef DEBUG
+  nsPrintfCString warning(
+      "Unknown virtual keycode (0x%08X), please check the "
+      "latest MSDN document, there may be some new "
+      "keycodes we've never known.",
+      aNativeKeyCode);
+  NS_WARNING(warning.get());
+#endif
+  return 0;
+}
+
+KeyNameIndex KeyboardLayout::ConvertNativeKeyCodeToKeyNameIndex(
+    uint8_t aVirtualKey) const {
+  if (IsPrintableCharKey(aVirtualKey) || aVirtualKey == VK_PACKET) {
+    return KEY_NAME_INDEX_USE_STRING;
+  }
+
+  // If the keyboard layout has AltGr and AltRight key is pressed,
+  // return AltGraph.
+  if (aVirtualKey == VK_RMENU && HasAltGr()) {
+    return KEY_NAME_INDEX_AltGraph;
+  }
+
+  switch (aVirtualKey) {
+#undef NS_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX
+#define NS_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX(aNativeKey, aKeyNameIndex) \
+  case aNativeKey:                                                     \
+    return aKeyNameIndex;
+
+#include "NativeKeyToDOMKeyName.h"
+
+#undef NS_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX
+
+    default:
+      break;
+  }
+
+  HKL layout = KeyboardLayout::GetLayout();
+  WORD langID = LOWORD(static_cast<HKL>(layout));
+  WORD primaryLangID = PRIMARYLANGID(langID);
+
+  if (primaryLangID == LANG_JAPANESE) {
+    switch (aVirtualKey) {
+#undef NS_JAPANESE_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX
+#define NS_JAPANESE_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX(aNativeKey,    \
+                                                     aKeyNameIndex) \
+  case aNativeKey:                                                  \
+    return aKeyNameIndex;
+
+#include "NativeKeyToDOMKeyName.h"
+
+#undef NS_JAPANESE_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX
+
+      default:
+        break;
+    }
+  } else if (primaryLangID == LANG_KOREAN) {
+    switch (aVirtualKey) {
+#undef NS_KOREAN_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX
+#define NS_KOREAN_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX(aNativeKey, aKeyNameIndex) \
+  case aNativeKey:                                                            \
+    return aKeyNameIndex;
+
+#include "NativeKeyToDOMKeyName.h"
+
+#undef NS_KOREAN_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX
+
+      default:
+        return KEY_NAME_INDEX_Unidentified;
+    }
+  }
+
+  switch (aVirtualKey) {
+#undef NS_OTHER_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX
+#define NS_OTHER_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX(aNativeKey, aKeyNameIndex) \
+  case aNativeKey:                                                           \
+    return aKeyNameIndex;
+
+#include "NativeKeyToDOMKeyName.h"
+
+#undef NS_OTHER_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX
+
+    default:
+      return KEY_NAME_INDEX_Unidentified;
+  }
+}
+
+// static
+CodeNameIndex KeyboardLayout::ConvertScanCodeToCodeNameIndex(UINT aScanCode) {
+  switch (aScanCode) {
+#define NS_NATIVE_KEY_TO_DOM_CODE_NAME_INDEX(aNativeKey, aCodeNameIndex) \
+  case aNativeKey:                                                       \
+    return aCodeNameIndex;
+
+#include "NativeKeyToDOMCodeName.h"
+
+#undef NS_NATIVE_KEY_TO_DOM_CODE_NAME_INDEX
+
+    default:
+      return CODE_NAME_INDEX_UNKNOWN;
+  }
+}
+
+nsresult KeyboardLayout::SynthesizeNativeKeyEvent(
+    nsWindow* aWidget, int32_t aNativeKeyboardLayout, int32_t aNativeKeyCode,
+    uint32_t aModifierFlags, const nsAString& aCharacters,
+    const nsAString& aUnmodifiedCharacters) {
+  UINT keyboardLayoutListCount = ::GetKeyboardLayoutList(0, nullptr);
+  NS_ASSERTION(keyboardLayoutListCount > 0,
+               "One keyboard layout must be installed at least");
+  HKL keyboardLayoutListBuff[50];
+  HKL* keyboardLayoutList = keyboardLayoutListCount < 50
+                                ? keyboardLayoutListBuff
+                                : new HKL[keyboardLayoutListCount];
+  keyboardLayoutListCount =
+      ::GetKeyboardLayoutList(keyboardLayoutListCount, keyboardLayoutList);
+  NS_ASSERTION(keyboardLayoutListCount > 0,
+               "Failed to get all keyboard layouts installed on the system");
+
+  nsPrintfCString layoutName("%08x", aNativeKeyboardLayout);
+  HKL loadedLayout = LoadKeyboardLayoutA(layoutName.get(), KLF_NOTELLSHELL);
+  if (loadedLayout == nullptr) {
+    if (keyboardLayoutListBuff != keyboardLayoutList) {
+      delete[] keyboardLayoutList;
+    }
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  // Setup clean key state and load desired layout
+  BYTE originalKbdState[256];
+  ::GetKeyboardState(originalKbdState);
+  BYTE kbdState[256];
+  memset(kbdState, 0, sizeof(kbdState));
+  // This changes the state of the keyboard for the current thread only,
+  // and we'll restore it soon, so this should be OK.
+  ::SetKeyboardState(kbdState);
+
+  OverrideLayout(loadedLayout);
+
+  bool isAltGrKeyPress = false;
+  if (aModifierFlags & nsIWidget::ALTGRAPH) {
+    if (!HasAltGr()) {
+      return NS_ERROR_INVALID_ARG;
+    }
+    // AltGr emulates ControlLeft key press and AltRight key press.
+    // So, we should remove those flags from aModifierFlags before
+    // calling WinUtils::SetupKeyModifiersSequence() to create correct
+    // key sequence.
+    // FYI: We don't support both ControlLeft and AltRight (AltGr) are
+    //      pressed at the same time unless synthesizing key is
+    //      VK_LCONTROL.
+    aModifierFlags &= ~(nsIWidget::CTRL_L | nsIWidget::ALT_R);
+  }
+
+  uint8_t argumentKeySpecific = 0;
+  switch (aNativeKeyCode & 0xFF) {
+    case VK_SHIFT:
+      aModifierFlags &= ~(nsIWidget::SHIFT_L | nsIWidget::SHIFT_R);
+      argumentKeySpecific = VK_LSHIFT;
+      break;
+    case VK_LSHIFT:
+      aModifierFlags &= ~nsIWidget::SHIFT_L;
+      argumentKeySpecific = aNativeKeyCode & 0xFF;
+      aNativeKeyCode = (aNativeKeyCode & 0xFFFF0000) | VK_SHIFT;
+      break;
+    case VK_RSHIFT:
+      aModifierFlags &= ~nsIWidget::SHIFT_R;
+      argumentKeySpecific = aNativeKeyCode & 0xFF;
+      aNativeKeyCode = (aNativeKeyCode & 0xFFFF0000) | VK_SHIFT;
+      break;
+    case VK_CONTROL:
+      aModifierFlags &= ~(nsIWidget::CTRL_L | nsIWidget::CTRL_R);
+      argumentKeySpecific = VK_LCONTROL;
+      break;
+    case VK_LCONTROL:
+      aModifierFlags &= ~nsIWidget::CTRL_L;
+      argumentKeySpecific = aNativeKeyCode & 0xFF;
+      aNativeKeyCode = (aNativeKeyCode & 0xFFFF0000) | VK_CONTROL;
+      break;
+    case VK_RCONTROL:
+      aModifierFlags &= ~nsIWidget::CTRL_R;
+      argumentKeySpecific = aNativeKeyCode & 0xFF;
+      aNativeKeyCode = (aNativeKeyCode & 0xFFFF0000) | VK_CONTROL;
+      break;
+    case VK_MENU:
+      aModifierFlags &= ~(nsIWidget::ALT_L | nsIWidget::ALT_R);
+      argumentKeySpecific = VK_LMENU;
+      break;
+    case VK_LMENU:
+      aModifierFlags &= ~nsIWidget::ALT_L;
+      argumentKeySpecific = aNativeKeyCode & 0xFF;
+      aNativeKeyCode = (aNativeKeyCode & 0xFFFF0000) | VK_MENU;
+      break;
+    case VK_RMENU:
+      aModifierFlags &= ~(nsIWidget::ALT_R | nsIWidget::ALTGRAPH);
+      argumentKeySpecific = aNativeKeyCode & 0xFF;
+      aNativeKeyCode = (aNativeKeyCode & 0xFFFF0000) | VK_MENU;
+      // If AltRight key is AltGr in the keyboard layout, let's use
+      // SetupKeyModifiersSequence() to emulate the native behavior
+      // since the same event order between keydown and keyup makes
+      // the following code complicated.
+      if (HasAltGr()) {
+        isAltGrKeyPress = true;
+        aModifierFlags &= ~nsIWidget::CTRL_L;
+        aModifierFlags |= nsIWidget::ALTGRAPH;
+      }
+      break;
+    case VK_CAPITAL:
+      aModifierFlags &= ~nsIWidget::CAPS_LOCK;
+      argumentKeySpecific = VK_CAPITAL;
+      break;
+    case VK_NUMLOCK:
+      aModifierFlags &= ~nsIWidget::NUM_LOCK;
+      argumentKeySpecific = VK_NUMLOCK;
+      break;
+  }
+
+  AutoTArray<KeyPair, 10> keySequence;
+  WinUtils::SetupKeyModifiersSequence(&keySequence, aModifierFlags, WM_KEYDOWN);
+  if (!isAltGrKeyPress) {
+    keySequence.AppendElement(KeyPair(aNativeKeyCode, argumentKeySpecific));
+  }
+
+  // Simulate the pressing of each modifier key and then the real key
+  // FYI: Each NativeKey instance here doesn't need to override keyboard layout
+  //      since this method overrides and restores the keyboard layout.
+  for (uint32_t i = 0; i < keySequence.Length(); ++i) {
+    uint8_t key = keySequence[i].mGeneral;
+    uint8_t keySpecific = keySequence[i].mSpecific;
+    uint16_t scanCode = keySequence[i].mScanCode;
+    kbdState[key] = 0x81;  // key is down and toggled on if appropriate
+    if (keySpecific) {
+      kbdState[keySpecific] = 0x81;
+    }
+    ::SetKeyboardState(kbdState);
+    ModifierKeyState modKeyState;
+    // If scan code isn't specified explicitly, let's compute it with current
+    // keyboard layout.
+    if (!scanCode) {
+      scanCode =
+          ComputeScanCodeForVirtualKeyCode(keySpecific ? keySpecific : key);
+    }
+    LPARAM lParam = static_cast<LPARAM>(scanCode << 16);
+    // If the scan code is for an extended key, set extended key flag.
+    if ((scanCode & 0xFF00) == 0xE000) {
+      lParam |= 0x1000000;
+    }
+    // When AltGr key is pressed, both ControlLeft and AltRight cause
+    // WM_KEYDOWN messages.
+    bool makeSysKeyMsg =
+        !(aModifierFlags & nsIWidget::ALTGRAPH) && IsSysKey(key, modKeyState);
+    MSG keyDownMsg =
+        WinUtils::InitMSG(makeSysKeyMsg ? WM_SYSKEYDOWN : WM_KEYDOWN, key,
+                          lParam, aWidget->GetWindowHandle());
+    if (i == keySequence.Length() - 1) {
+      bool makeDeadCharMsg =
+          (IsDeadKey(key, modKeyState) && aCharacters.IsEmpty());
+      nsAutoString chars(aCharacters);
+      if (makeDeadCharMsg) {
+        UniCharsAndModifiers deadChars =
+            GetUniCharsAndModifiers(key, modKeyState);
+        chars = deadChars.ToString();
+        NS_ASSERTION(chars.Length() == 1,
+                     "Dead char must be only one character");
+      }
+      if (chars.IsEmpty()) {
+        NativeKey nativeKey(aWidget, keyDownMsg, modKeyState);
+        nativeKey.HandleKeyDownMessage();
+      } else {
+        AutoTArray<NativeKey::FakeCharMsg, 10> fakeCharMsgs;
+        for (uint32_t j = 0; j < chars.Length(); j++) {
+          NativeKey::FakeCharMsg* fakeCharMsg = fakeCharMsgs.AppendElement();
+          fakeCharMsg->mCharCode = chars.CharAt(j);
+          fakeCharMsg->mScanCode = scanCode;
+          fakeCharMsg->mIsSysKey = makeSysKeyMsg;
+          fakeCharMsg->mIsDeadKey = makeDeadCharMsg;
+        }
+        NativeKey nativeKey(aWidget, keyDownMsg, modKeyState, 0, &fakeCharMsgs);
+        bool dispatched;
+        nativeKey.HandleKeyDownMessage(&dispatched);
+        // If some char messages are not consumed, let's emulate the widget
+        // receiving the message directly.
+        for (uint32_t j = 1; j < fakeCharMsgs.Length(); j++) {
+          if (fakeCharMsgs[j].mConsumed) {
+            continue;
+          }
+          MSG charMsg = fakeCharMsgs[j].GetCharMsg(aWidget->GetWindowHandle());
+          NativeKey nativeKey(aWidget, charMsg, modKeyState);
+          nativeKey.HandleCharMessage(charMsg);
+        }
+      }
+    } else {
+      NativeKey nativeKey(aWidget, keyDownMsg, modKeyState);
+      nativeKey.HandleKeyDownMessage();
+    }
+  }
+
+  keySequence.Clear();
+  if (!isAltGrKeyPress) {
+    keySequence.AppendElement(KeyPair(aNativeKeyCode, argumentKeySpecific));
+  }
+  WinUtils::SetupKeyModifiersSequence(&keySequence, aModifierFlags, WM_KEYUP);
+  for (uint32_t i = 0; i < keySequence.Length(); ++i) {
+    uint8_t key = keySequence[i].mGeneral;
+    uint8_t keySpecific = keySequence[i].mSpecific;
+    uint16_t scanCode = keySequence[i].mScanCode;
+    kbdState[key] = 0;  // key is up and toggled off if appropriate
+    if (keySpecific) {
+      kbdState[keySpecific] = 0;
+    }
+    ::SetKeyboardState(kbdState);
+    ModifierKeyState modKeyState;
+    // If scan code isn't specified explicitly, let's compute it with current
+    // keyboard layout.
+    if (!scanCode) {
+      scanCode =
+          ComputeScanCodeForVirtualKeyCode(keySpecific ? keySpecific : key);
+    }
+    LPARAM lParam = static_cast<LPARAM>(scanCode << 16);
+    // If the scan code is for an extended key, set extended key flag.
+    if ((scanCode & 0xFF00) == 0xE000) {
+      lParam |= 0x1000000;
+    }
+    // Don't use WM_SYSKEYUP for Alt keyup.
+    // NOTE: When AltGr was pressed, ControlLeft causes WM_SYSKEYUP normally.
+    bool makeSysKeyMsg = IsSysKey(key, modKeyState) && key != VK_MENU;
+    MSG keyUpMsg = WinUtils::InitMSG(makeSysKeyMsg ? WM_SYSKEYUP : WM_KEYUP,
+                                     key, lParam, aWidget->GetWindowHandle());
+    NativeKey nativeKey(aWidget, keyUpMsg, modKeyState);
+    nativeKey.HandleKeyUpMessage();
+  }
+
+  // Restore old key state and layout
+  ::SetKeyboardState(originalKbdState);
+  RestoreLayout();
+
+  // Don't unload the layout if it's installed actually.
+  for (uint32_t i = 0; i < keyboardLayoutListCount; i++) {
+    if (keyboardLayoutList[i] == loadedLayout) {
+      loadedLayout = 0;
+      break;
+    }
+  }
+  if (keyboardLayoutListBuff != keyboardLayoutList) {
+    delete[] keyboardLayoutList;
+  }
+  if (loadedLayout) {
+    ::UnloadKeyboardLayout(loadedLayout);
+  }
+  return NS_OK;
+}
+
+/*****************************************************************************
+ * mozilla::widget::DeadKeyTable
+ *****************************************************************************/
+
+char16_t DeadKeyTable::GetCompositeChar(char16_t aBaseChar) const {
+  // Dead-key table is sorted by BaseChar in ascending order.
+  // Usually they are too small to use binary search.
+
+  for (uint32_t index = 0; index < mEntries; index++) {
+    if (mTable[index].BaseChar == aBaseChar) {
+      return mTable[index].CompositeChar;
+    }
+    if (mTable[index].BaseChar > aBaseChar) {
+      break;
+    }
+  }
+
+  return 0;
+}
+
+/*****************************************************************************
+ * mozilla::widget::RedirectedKeyDownMessage
+ *****************************************************************************/
+
+MSG RedirectedKeyDownMessageManager::sRedirectedKeyDownMsg;
+bool RedirectedKeyDownMessageManager::sDefaultPreventedOfRedirectedMsg = false;
+
+// static
+bool RedirectedKeyDownMessageManager::IsRedirectedMessage(const MSG& aMsg) {
+  return (aMsg.message == WM_KEYDOWN || aMsg.message == WM_SYSKEYDOWN) &&
+         (sRedirectedKeyDownMsg.message == aMsg.message &&
+          WinUtils::GetScanCode(sRedirectedKeyDownMsg.lParam) ==
+              WinUtils::GetScanCode(aMsg.lParam));
+}
+
+// static
+void RedirectedKeyDownMessageManager::RemoveNextCharMessage(HWND aWnd) {
+  MSG msg;
+  if (WinUtils::PeekMessage(&msg, aWnd, WM_KEYFIRST, WM_KEYLAST,
+                            PM_NOREMOVE | PM_NOYIELD) &&
+      (msg.message == WM_CHAR || msg.message == WM_SYSCHAR)) {
+    WinUtils::PeekMessage(&msg, aWnd, msg.message, msg.message,
+                          PM_REMOVE | PM_NOYIELD);
+  }
+}
+
+}  // namespace widget
+}  // namespace mozilla