Add m-esr52 at 52.6.0

1 files changed, 1474 insertions, 0 deletions

diff --git a/layout/base/AccessibleCaretManager.cpp b/layout/base/AccessibleCaretManager.cpp
new file mode 100644
index 000000000..ac3f36bea
--- /dev/null
+++ b/layout/base/AccessibleCaretManager.cpp
@@ -0,0 +1,1474 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "AccessibleCaretManager.h"
+
+#include "AccessibleCaret.h"
+#include "AccessibleCaretEventHub.h"
+#include "AccessibleCaretLogger.h"
+#include "mozilla/AsyncEventDispatcher.h"
+#include "mozilla/dom/Element.h"
+#include "mozilla/dom/Selection.h"
+#include "mozilla/dom/TreeWalker.h"
+#include "mozilla/IMEStateManager.h"
+#include "mozilla/Preferences.h"
+#include "nsCaret.h"
+#include "nsContainerFrame.h"
+#include "nsContentUtils.h"
+#include "nsFocusManager.h"
+#include "nsFrame.h"
+#include "nsFrameSelection.h"
+#include "nsGenericHTMLElement.h"
+#include "nsIHapticFeedback.h"
+#ifdef MOZ_WIDGET_ANDROID
+#include "nsWindow.h"
+#endif
+
+namespace mozilla {
+
+#undef AC_LOG
+#define AC_LOG(message, ...)                                                   \
+  AC_LOG_BASE("AccessibleCaretManager (%p): " message, this, ##__VA_ARGS__);
+
+#undef AC_LOGV
+#define AC_LOGV(message, ...)                                                  \
+  AC_LOGV_BASE("AccessibleCaretManager (%p): " message, this, ##__VA_ARGS__);
+
+using namespace dom;
+using Appearance = AccessibleCaret::Appearance;
+using PositionChangedResult = AccessibleCaret::PositionChangedResult;
+
+#define AC_PROCESS_ENUM_TO_STREAM(e) case(e): aStream << #e; break;
+std::ostream&
+operator<<(std::ostream& aStream,
+           const AccessibleCaretManager::CaretMode& aCaretMode)
+{
+  using CaretMode = AccessibleCaretManager::CaretMode;
+  switch (aCaretMode) {
+    AC_PROCESS_ENUM_TO_STREAM(CaretMode::None);
+    AC_PROCESS_ENUM_TO_STREAM(CaretMode::Cursor);
+    AC_PROCESS_ENUM_TO_STREAM(CaretMode::Selection);
+  }
+  return aStream;
+}
+
+std::ostream& operator<<(std::ostream& aStream,
+                         const AccessibleCaretManager::UpdateCaretsHint& aHint)
+{
+  using UpdateCaretsHint = AccessibleCaretManager::UpdateCaretsHint;
+  switch (aHint) {
+    AC_PROCESS_ENUM_TO_STREAM(UpdateCaretsHint::Default);
+    AC_PROCESS_ENUM_TO_STREAM(UpdateCaretsHint::RespectOldAppearance);
+  }
+  return aStream;
+}
+#undef AC_PROCESS_ENUM_TO_STREAM
+
+/*static*/ bool
+AccessibleCaretManager::sSelectionBarEnabled = false;
+/*static*/ bool
+AccessibleCaretManager::sCaretShownWhenLongTappingOnEmptyContent = false;
+/*static*/ bool
+AccessibleCaretManager::sCaretsAlwaysTilt = false;
+/*static*/ bool
+AccessibleCaretManager::sCaretsAlwaysShowWhenScrolling = true;
+/*static*/ bool
+AccessibleCaretManager::sCaretsScriptUpdates = false;
+/*static*/ bool
+AccessibleCaretManager::sCaretsAllowDraggingAcrossOtherCaret = true;
+/*static*/ bool
+AccessibleCaretManager::sHapticFeedback = false;
+/*static*/ bool
+AccessibleCaretManager::sExtendSelectionForPhoneNumber = false;
+/*static*/ bool
+AccessibleCaretManager::sHideCaretsForMouseInput = true;
+
+AccessibleCaretManager::AccessibleCaretManager(nsIPresShell* aPresShell)
+  : mPresShell(aPresShell)
+{
+  if (!mPresShell) {
+    return;
+  }
+
+  mFirstCaret = MakeUnique<AccessibleCaret>(mPresShell);
+  mSecondCaret = MakeUnique<AccessibleCaret>(mPresShell);
+
+  mCaretTimeoutTimer = do_CreateInstance("@mozilla.org/timer;1");
+
+  static bool addedPrefs = false;
+  if (!addedPrefs) {
+    Preferences::AddBoolVarCache(&sSelectionBarEnabled,
+                                 "layout.accessiblecaret.bar.enabled");
+    Preferences::AddBoolVarCache(&sCaretShownWhenLongTappingOnEmptyContent,
+      "layout.accessiblecaret.caret_shown_when_long_tapping_on_empty_content");
+    Preferences::AddBoolVarCache(&sCaretsAlwaysTilt,
+                                 "layout.accessiblecaret.always_tilt");
+    Preferences::AddBoolVarCache(&sCaretsAlwaysShowWhenScrolling,
+      "layout.accessiblecaret.always_show_when_scrolling", true);
+    Preferences::AddBoolVarCache(&sCaretsScriptUpdates,
+      "layout.accessiblecaret.allow_script_change_updates");
+    Preferences::AddBoolVarCache(&sCaretsAllowDraggingAcrossOtherCaret,
+      "layout.accessiblecaret.allow_dragging_across_other_caret", true);
+    Preferences::AddBoolVarCache(&sHapticFeedback,
+                                 "layout.accessiblecaret.hapticfeedback");
+    Preferences::AddBoolVarCache(&sExtendSelectionForPhoneNumber,
+      "layout.accessiblecaret.extend_selection_for_phone_number");
+    Preferences::AddBoolVarCache(&sHideCaretsForMouseInput,
+      "layout.accessiblecaret.hide_carets_for_mouse_input");
+    addedPrefs = true;
+  }
+}
+
+AccessibleCaretManager::~AccessibleCaretManager()
+{
+}
+
+void
+AccessibleCaretManager::Terminate()
+{
+  CancelCaretTimeoutTimer();
+  mCaretTimeoutTimer = nullptr;
+  mFirstCaret = nullptr;
+  mSecondCaret = nullptr;
+  mActiveCaret = nullptr;
+  mPresShell = nullptr;
+}
+
+nsresult
+AccessibleCaretManager::OnSelectionChanged(nsIDOMDocument* aDoc,
+                                           nsISelection* aSel, int16_t aReason)
+{
+  Selection* selection = GetSelection();
+  AC_LOG("%s: aSel: %p, GetSelection(): %p, aReason: %d", __FUNCTION__,
+         aSel, selection, aReason);
+  if (aSel != selection) {
+    return NS_OK;
+  }
+
+  // eSetSelection events from the Fennec widget IME can be generated
+  // by autoSuggest / autoCorrect composition changes, or by TYPE_REPLACE_TEXT
+  // actions, either positioning cursor for text insert, or selecting
+  // text-to-be-replaced. None should affect AccessibleCaret visibility.
+  if (aReason & nsISelectionListener::IME_REASON) {
+    return NS_OK;
+  }
+
+  // Move the cursor by Javascript / or unknown internal.
+  if (aReason == nsISelectionListener::NO_REASON) {
+    // Update visible carets, if javascript changes are allowed.
+    if (sCaretsScriptUpdates &&
+        (mFirstCaret->IsLogicallyVisible() || mSecondCaret->IsLogicallyVisible())) {
+        UpdateCarets();
+        return NS_OK;
+    }
+    // Default for NO_REASON is to make hidden.
+    HideCarets();
+    return NS_OK;
+  }
+
+  // Move cursor by keyboard.
+  if (aReason & nsISelectionListener::KEYPRESS_REASON) {
+    HideCarets();
+    return NS_OK;
+  }
+
+  // OnBlur() might be called between mouse down and mouse up, so we hide carets
+  // upon mouse down anyway, and update carets upon mouse up.
+  if (aReason & nsISelectionListener::MOUSEDOWN_REASON) {
+    HideCarets();
+    return NS_OK;
+  }
+
+  // Range will collapse after cutting or copying text.
+  if (aReason & (nsISelectionListener::COLLAPSETOSTART_REASON |
+                 nsISelectionListener::COLLAPSETOEND_REASON)) {
+    HideCarets();
+    return NS_OK;
+  }
+
+  // For mouse input we don't want to show the carets.
+  if (sHideCaretsForMouseInput &&
+      mLastInputSource == nsIDOMMouseEvent::MOZ_SOURCE_MOUSE) {
+    HideCarets();
+    return NS_OK;
+  }
+
+  // When we want to hide the carets for mouse input, hide them for select
+  // all action fired by keyboard as well.
+  if (sHideCaretsForMouseInput &&
+      mLastInputSource == nsIDOMMouseEvent::MOZ_SOURCE_KEYBOARD &&
+      (aReason & nsISelectionListener::SELECTALL_REASON)) {
+    HideCarets();
+    return NS_OK;
+  }
+
+  UpdateCarets();
+  return NS_OK;
+}
+
+void
+AccessibleCaretManager::HideCarets()
+{
+  if (mFirstCaret->IsLogicallyVisible() || mSecondCaret->IsLogicallyVisible()) {
+    AC_LOG("%s", __FUNCTION__);
+    mFirstCaret->SetAppearance(Appearance::None);
+    mSecondCaret->SetAppearance(Appearance::None);
+    DispatchCaretStateChangedEvent(CaretChangedReason::Visibilitychange);
+    CancelCaretTimeoutTimer();
+  }
+}
+
+void
+AccessibleCaretManager::UpdateCarets(UpdateCaretsHint aHint)
+{
+  FlushLayout();
+  if (IsTerminated()) {
+    return;
+  }
+
+  mLastUpdateCaretMode = GetCaretMode();
+
+  switch (mLastUpdateCaretMode) {
+  case CaretMode::None:
+    HideCarets();
+    break;
+  case CaretMode::Cursor:
+    UpdateCaretsForCursorMode(aHint);
+    break;
+  case CaretMode::Selection:
+    UpdateCaretsForSelectionMode(aHint);
+    break;
+  }
+}
+
+bool
+AccessibleCaretManager::IsCaretDisplayableInCursorMode(nsIFrame** aOutFrame,
+                                                       int32_t* aOutOffset) const
+{
+  RefPtr<nsCaret> caret = mPresShell->GetCaret();
+  if (!caret || !caret->IsVisible()) {
+    return false;
+  }
+
+  int32_t offset = 0;
+  nsIFrame* frame = nsCaret::GetFrameAndOffset(GetSelection(), nullptr, 0, &offset);
+
+  if (!frame) {
+    return false;
+  }
+
+  if (!GetEditingHostForFrame(frame)) {
+    return false;
+  }
+
+  if (aOutFrame) {
+    *aOutFrame = frame;
+  }
+
+  if (aOutOffset) {
+    *aOutOffset = offset;
+  }
+
+  return true;
+}
+
+bool
+AccessibleCaretManager::HasNonEmptyTextContent(nsINode* aNode) const
+{
+  return nsContentUtils::HasNonEmptyTextContent(
+           aNode, nsContentUtils::eRecurseIntoChildren);
+}
+
+void
+AccessibleCaretManager::UpdateCaretsForCursorMode(UpdateCaretsHint aHint)
+{
+  AC_LOG("%s, selection: %p", __FUNCTION__, GetSelection());
+
+  int32_t offset = 0;
+  nsIFrame* frame = nullptr;
+  if (!IsCaretDisplayableInCursorMode(&frame, &offset)) {
+    HideCarets();
+    return;
+  }
+
+  bool oldSecondCaretVisible = mSecondCaret->IsLogicallyVisible();
+  PositionChangedResult result = mFirstCaret->SetPosition(frame, offset);
+
+  switch (result) {
+    case PositionChangedResult::NotChanged:
+      // Do nothing
+      break;
+
+    case PositionChangedResult::Changed:
+      switch (aHint) {
+        case UpdateCaretsHint::Default:
+          if (HasNonEmptyTextContent(GetEditingHostForFrame(frame))) {
+            mFirstCaret->SetAppearance(Appearance::Normal);
+          } else if (sCaretShownWhenLongTappingOnEmptyContent) {
+            if (mFirstCaret->IsLogicallyVisible()) {
+              // Possible cases are: 1) SelectWordOrShortcut() sets the
+              // appearance to Normal. 2) When the caret is out of viewport and
+              // now scrolling into viewport, it has appearance NormalNotShown.
+              mFirstCaret->SetAppearance(Appearance::Normal);
+            } else {
+              // Possible cases are: a) Single tap on current empty content;
+              // OnSelectionChanged() sets the appearance to None due to
+              // MOUSEDOWN_REASON. b) Single tap on other empty content;
+              // OnBlur() sets the appearance to None.
+              //
+              // Do nothing to make the appearance remains None so that it can
+              // be distinguished from case 2). Also do not set the appearance
+              // to NormalNotShown here like the default update behavior.
+            }
+          } else {
+            mFirstCaret->SetAppearance(Appearance::NormalNotShown);
+          }
+          break;
+
+        case UpdateCaretsHint::RespectOldAppearance:
+          // Do nothing to preserve the appearance of the caret set by the
+          // caller.
+          break;
+      }
+      break;
+
+    case PositionChangedResult::Invisible:
+      mFirstCaret->SetAppearance(Appearance::NormalNotShown);
+      break;
+  }
+
+  mFirstCaret->SetSelectionBarEnabled(false);
+  mSecondCaret->SetAppearance(Appearance::None);
+
+  LaunchCaretTimeoutTimer();
+
+  if ((result != PositionChangedResult::NotChanged || oldSecondCaretVisible) &&
+      !mActiveCaret) {
+    DispatchCaretStateChangedEvent(CaretChangedReason::Updateposition);
+  }
+}
+
+void
+AccessibleCaretManager::UpdateCaretsForSelectionMode(UpdateCaretsHint aHint)
+{
+  AC_LOG("%s: selection: %p", __FUNCTION__, GetSelection());
+
+  int32_t startOffset = 0;
+  nsIFrame* startFrame =
+    GetFrameForFirstRangeStartOrLastRangeEnd(eDirNext, &startOffset);
+
+  int32_t endOffset = 0;
+  nsIFrame* endFrame =
+    GetFrameForFirstRangeStartOrLastRangeEnd(eDirPrevious, &endOffset);
+
+  if (!CompareTreePosition(startFrame, endFrame)) {
+    // XXX: Do we really have to hide carets if this condition isn't satisfied?
+    HideCarets();
+    return;
+  }
+
+  auto updateSingleCaret = [aHint](AccessibleCaret* aCaret, nsIFrame* aFrame,
+                                   int32_t aOffset) -> PositionChangedResult
+  {
+    PositionChangedResult result = aCaret->SetPosition(aFrame, aOffset);
+    aCaret->SetSelectionBarEnabled(sSelectionBarEnabled);
+
+    switch (result) {
+      case PositionChangedResult::NotChanged:
+        // Do nothing
+        break;
+
+      case PositionChangedResult::Changed:
+        switch (aHint) {
+          case UpdateCaretsHint::Default:
+            aCaret->SetAppearance(Appearance::Normal);
+            break;
+
+          case UpdateCaretsHint::RespectOldAppearance:
+            // Do nothing to preserve the appearance of the caret set by the
+            // caller.
+            break;
+        }
+        break;
+
+      case PositionChangedResult::Invisible:
+        aCaret->SetAppearance(Appearance::NormalNotShown);
+        break;
+    }
+    return result;
+  };
+
+  PositionChangedResult firstCaretResult =
+    updateSingleCaret(mFirstCaret.get(), startFrame, startOffset);
+  PositionChangedResult secondCaretResult =
+    updateSingleCaret(mSecondCaret.get(), endFrame, endOffset);
+
+  if (firstCaretResult == PositionChangedResult::Changed ||
+      secondCaretResult == PositionChangedResult::Changed) {
+    // Flush layout to make the carets intersection correct.
+    FlushLayout();
+    if (IsTerminated()) {
+      return;
+    }
+  }
+
+  if (aHint == UpdateCaretsHint::Default) {
+    // Only check for tilt carets with default update hint. Otherwise we might
+    // override the appearance set by the caller.
+    if (sCaretsAlwaysTilt) {
+      UpdateCaretsForAlwaysTilt(startFrame, endFrame);
+    } else {
+      UpdateCaretsForOverlappingTilt();
+    }
+  }
+
+  if (!mActiveCaret) {
+    DispatchCaretStateChangedEvent(CaretChangedReason::Updateposition);
+  }
+}
+
+void
+AccessibleCaretManager::UpdateCaretsForOverlappingTilt()
+{
+  if (mFirstCaret->IsVisuallyVisible() && mSecondCaret->IsVisuallyVisible()) {
+    if (mFirstCaret->Intersects(*mSecondCaret)) {
+      if (mFirstCaret->LogicalPosition().x <=
+          mSecondCaret->LogicalPosition().x) {
+        mFirstCaret->SetAppearance(Appearance::Left);
+        mSecondCaret->SetAppearance(Appearance::Right);
+      } else {
+        mFirstCaret->SetAppearance(Appearance::Right);
+        mSecondCaret->SetAppearance(Appearance::Left);
+      }
+    } else {
+      mFirstCaret->SetAppearance(Appearance::Normal);
+      mSecondCaret->SetAppearance(Appearance::Normal);
+    }
+  }
+}
+
+void
+AccessibleCaretManager::UpdateCaretsForAlwaysTilt(nsIFrame* aStartFrame,
+                                                  nsIFrame* aEndFrame)
+{
+  if (mFirstCaret->IsVisuallyVisible()) {
+    auto startFrameWritingMode = aStartFrame->GetWritingMode();
+    mFirstCaret->SetAppearance(startFrameWritingMode.IsBidiLTR() ?
+                               Appearance::Left : Appearance::Right);
+  }
+  if (mSecondCaret->IsVisuallyVisible()) {
+    auto endFrameWritingMode = aEndFrame->GetWritingMode();
+    mSecondCaret->SetAppearance(endFrameWritingMode.IsBidiLTR() ?
+                                Appearance::Right : Appearance::Left);
+  }
+}
+
+void
+AccessibleCaretManager::ProvideHapticFeedback()
+{
+  if (sHapticFeedback) {
+    nsCOMPtr<nsIHapticFeedback> haptic =
+      do_GetService("@mozilla.org/widget/hapticfeedback;1");
+    haptic->PerformSimpleAction(haptic->LongPress);
+  }
+}
+
+nsresult
+AccessibleCaretManager::PressCaret(const nsPoint& aPoint,
+                                   EventClassID aEventClass)
+{
+  nsresult rv = NS_ERROR_FAILURE;
+
+  MOZ_ASSERT(aEventClass == eMouseEventClass || aEventClass == eTouchEventClass,
+             "Unexpected event class!");
+
+  using TouchArea = AccessibleCaret::TouchArea;
+  TouchArea touchArea =
+    aEventClass == eMouseEventClass ? TouchArea::CaretImage : TouchArea::Full;
+
+  if (mFirstCaret->Contains(aPoint, touchArea)) {
+    mActiveCaret = mFirstCaret.get();
+    SetSelectionDirection(eDirPrevious);
+  } else if (mSecondCaret->Contains(aPoint, touchArea)) {
+    mActiveCaret = mSecondCaret.get();
+    SetSelectionDirection(eDirNext);
+  }
+
+  if (mActiveCaret) {
+    mOffsetYToCaretLogicalPosition =
+      mActiveCaret->LogicalPosition().y - aPoint.y;
+    SetSelectionDragState(true);
+    DispatchCaretStateChangedEvent(CaretChangedReason::Presscaret);
+    CancelCaretTimeoutTimer();
+    rv = NS_OK;
+  }
+
+  return rv;
+}
+
+nsresult
+AccessibleCaretManager::DragCaret(const nsPoint& aPoint)
+{
+  MOZ_ASSERT(mActiveCaret);
+  MOZ_ASSERT(GetCaretMode() != CaretMode::None);
+
+  nsPoint point(aPoint.x, aPoint.y + mOffsetYToCaretLogicalPosition);
+  DragCaretInternal(point);
+  UpdateCarets();
+  return NS_OK;
+}
+
+nsresult
+AccessibleCaretManager::ReleaseCaret()
+{
+  MOZ_ASSERT(mActiveCaret);
+
+  mActiveCaret = nullptr;
+  SetSelectionDragState(false);
+  DispatchCaretStateChangedEvent(CaretChangedReason::Releasecaret);
+  LaunchCaretTimeoutTimer();
+  return NS_OK;
+}
+
+nsresult
+AccessibleCaretManager::TapCaret(const nsPoint& aPoint)
+{
+  MOZ_ASSERT(GetCaretMode() != CaretMode::None);
+
+  nsresult rv = NS_ERROR_FAILURE;
+
+  if (GetCaretMode() == CaretMode::Cursor) {
+    DispatchCaretStateChangedEvent(CaretChangedReason::Taponcaret);
+    rv = NS_OK;
+  }
+
+  return rv;
+}
+
+nsresult
+AccessibleCaretManager::SelectWordOrShortcut(const nsPoint& aPoint)
+{
+  auto UpdateCaretsWithHapticFeedback = [this] {
+    UpdateCarets();
+    ProvideHapticFeedback();
+  };
+
+  // If the long-tap is landing on a pre-existing selection, don't replace
+  // it with a new one. Instead just return and let the context menu pop up
+  // on the pre-existing selection.
+  if (GetCaretMode() == CaretMode::Selection &&
+      GetSelection()->ContainsPoint(aPoint)) {
+    AC_LOG("%s: UpdateCarets() for current selection", __FUNCTION__);
+    UpdateCaretsWithHapticFeedback();
+    return NS_OK;
+  }
+
+  if (!mPresShell) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsIFrame* rootFrame = mPresShell->GetRootFrame();
+  if (!rootFrame) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  // Find the frame under point.
+  nsWeakFrame ptFrame = nsLayoutUtils::GetFrameForPoint(rootFrame, aPoint,
+    nsLayoutUtils::IGNORE_PAINT_SUPPRESSION | nsLayoutUtils::IGNORE_CROSS_DOC);
+  if (!ptFrame.IsAlive()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsIFrame* focusableFrame = GetFocusableFrame(ptFrame);
+
+#ifdef DEBUG_FRAME_DUMP
+  AC_LOG("%s: Found %s under (%d, %d)", __FUNCTION__, ptFrame->ListTag().get(),
+         aPoint.x, aPoint.y);
+  AC_LOG("%s: Found %s focusable", __FUNCTION__,
+         focusableFrame ? focusableFrame->ListTag().get() : "no frame");
+#endif
+
+  // Get ptInFrame here so that we don't need to check whether rootFrame is
+  // alive later. Note that if ptFrame is being moved by
+  // IMEStateManager::NotifyIME() or ChangeFocusToOrClearOldFocus() below,
+  // something under the original point will be selected, which may not be the
+  // original text the user wants to select.
+  nsPoint ptInFrame = aPoint;
+  nsLayoutUtils::TransformPoint(rootFrame, ptFrame, ptInFrame);
+
+  // Firstly check long press on an empty editable content.
+  Element* newFocusEditingHost = GetEditingHostForFrame(ptFrame);
+  if (focusableFrame && newFocusEditingHost &&
+      !HasNonEmptyTextContent(newFocusEditingHost)) {
+    ChangeFocusToOrClearOldFocus(focusableFrame);
+
+    if (sCaretShownWhenLongTappingOnEmptyContent) {
+      mFirstCaret->SetAppearance(Appearance::Normal);
+    }
+    // We need to update carets to get correct information before dispatching
+    // CaretStateChangedEvent.
+    UpdateCaretsWithHapticFeedback();
+    DispatchCaretStateChangedEvent(CaretChangedReason::Longpressonemptycontent);
+    return NS_OK;
+  }
+
+  bool selectable = false;
+  ptFrame->IsSelectable(&selectable, nullptr);
+
+#ifdef DEBUG_FRAME_DUMP
+  AC_LOG("%s: %s %s selectable.", __FUNCTION__, ptFrame->ListTag().get(),
+         selectable ? "is" : "is NOT");
+#endif
+
+  if (!selectable) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Commit the composition string of the old editable focus element (if there
+  // is any) before changing the focus.
+  IMEStateManager::NotifyIME(widget::REQUEST_TO_COMMIT_COMPOSITION,
+                             mPresShell->GetPresContext());
+  if (!ptFrame.IsAlive()) {
+    // Cannot continue because ptFrame died.
+    return NS_ERROR_FAILURE;
+  }
+
+  // ptFrame is selectable. Now change the focus.
+  ChangeFocusToOrClearOldFocus(focusableFrame);
+  if (!ptFrame.IsAlive()) {
+    // Cannot continue because ptFrame died.
+    return NS_ERROR_FAILURE;
+  }
+
+  // Then try select a word under point.
+  nsresult rv = SelectWord(ptFrame, ptInFrame);
+  UpdateCaretsWithHapticFeedback();
+
+  return rv;
+}
+
+void
+AccessibleCaretManager::OnScrollStart()
+{
+  AC_LOG("%s", __FUNCTION__);
+
+  if (!sCaretsAlwaysShowWhenScrolling) {
+    // Backup the appearance so that we can restore them after the scrolling
+    // ends.
+    mFirstCaretAppearanceOnScrollStart = mFirstCaret->GetAppearance();
+    mSecondCaretAppearanceOnScrollStart = mSecondCaret->GetAppearance();
+    HideCarets();
+    return;
+  }
+
+  if (mFirstCaret->IsLogicallyVisible() || mSecondCaret->IsLogicallyVisible()) {
+    // Dispatch the event only if one of the carets is logically visible like in
+    // HideCarets().
+    DispatchCaretStateChangedEvent(CaretChangedReason::Scroll);
+  }
+}
+
+void
+AccessibleCaretManager::OnScrollEnd()
+{
+  if (mLastUpdateCaretMode != GetCaretMode()) {
+    return;
+  }
+
+  if (!sCaretsAlwaysShowWhenScrolling) {
+    // Restore the appearance which is saved before the scrolling is started.
+    mFirstCaret->SetAppearance(mFirstCaretAppearanceOnScrollStart);
+    mSecondCaret->SetAppearance(mSecondCaretAppearanceOnScrollStart);
+  }
+
+  if (GetCaretMode() == CaretMode::Cursor) {
+    if (!mFirstCaret->IsLogicallyVisible()) {
+      // If the caret is hidden (Appearance::None) due to timeout or blur, no
+      // need to update it.
+      return;
+    }
+  }
+
+  // For mouse input we don't want to show the carets.
+  if (sHideCaretsForMouseInput &&
+      mLastInputSource == nsIDOMMouseEvent::MOZ_SOURCE_MOUSE) {
+    AC_LOG("%s: HideCarets()", __FUNCTION__);
+    HideCarets();
+    return;
+  }
+
+  AC_LOG("%s: UpdateCarets()", __FUNCTION__);
+  UpdateCarets();
+}
+
+void
+AccessibleCaretManager::OnScrollPositionChanged()
+{
+  if (mLastUpdateCaretMode != GetCaretMode()) {
+    return;
+  }
+
+  if (mFirstCaret->IsLogicallyVisible() || mSecondCaret->IsLogicallyVisible()) {
+    AC_LOG("%s: UpdateCarets(RespectOldAppearance)", __FUNCTION__);
+    UpdateCarets(UpdateCaretsHint::RespectOldAppearance);
+  }
+}
+
+void
+AccessibleCaretManager::OnReflow()
+{
+  if (mLastUpdateCaretMode != GetCaretMode()) {
+    return;
+  }
+
+  if (mFirstCaret->IsLogicallyVisible() || mSecondCaret->IsLogicallyVisible()) {
+    AC_LOG("%s: UpdateCarets(RespectOldAppearance)", __FUNCTION__);
+    UpdateCarets(UpdateCaretsHint::RespectOldAppearance);
+  }
+}
+
+void
+AccessibleCaretManager::OnBlur()
+{
+  AC_LOG("%s: HideCarets()", __FUNCTION__);
+  HideCarets();
+}
+
+void
+AccessibleCaretManager::OnKeyboardEvent()
+{
+  if (GetCaretMode() == CaretMode::Cursor) {
+    AC_LOG("%s: HideCarets()", __FUNCTION__);
+    HideCarets();
+  }
+}
+
+void
+AccessibleCaretManager::OnFrameReconstruction()
+{
+  mFirstCaret->EnsureApzAware();
+  mSecondCaret->EnsureApzAware();
+}
+
+void
+AccessibleCaretManager::SetLastInputSource(uint16_t aInputSource)
+{
+  mLastInputSource = aInputSource;
+}
+
+Selection*
+AccessibleCaretManager::GetSelection() const
+{
+  RefPtr<nsFrameSelection> fs = GetFrameSelection();
+  if (!fs) {
+    return nullptr;
+  }
+  return fs->GetSelection(SelectionType::eNormal);
+}
+
+already_AddRefed<nsFrameSelection>
+AccessibleCaretManager::GetFrameSelection() const
+{
+  if (!mPresShell) {
+    return nullptr;
+  }
+
+  nsFocusManager* fm = nsFocusManager::GetFocusManager();
+  MOZ_ASSERT(fm);
+
+  nsIContent* focusedContent = fm->GetFocusedContent();
+  if (focusedContent) {
+    nsIFrame* focusFrame = focusedContent->GetPrimaryFrame();
+    if (!focusFrame) {
+      return nullptr;
+    }
+
+    // Prevent us from touching the nsFrameSelection associated with other
+    // PresShell.
+    RefPtr<nsFrameSelection> fs = focusFrame->GetFrameSelection();
+    if (!fs || fs->GetShell() != mPresShell) {
+      return nullptr;
+    }
+
+    return fs.forget();
+  } else {
+    // For non-editable content
+    return mPresShell->FrameSelection();
+  }
+}
+
+Element*
+AccessibleCaretManager::GetEditingHostForFrame(nsIFrame* aFrame) const
+{
+  if (!aFrame) {
+    return nullptr;
+  }
+
+  auto content = aFrame->GetContent();
+  if (!content) {
+    return nullptr;
+  }
+
+  return content->GetEditingHost();
+}
+
+
+AccessibleCaretManager::CaretMode
+AccessibleCaretManager::GetCaretMode() const
+{
+  Selection* selection = GetSelection();
+  if (!selection) {
+    return CaretMode::None;
+  }
+
+  uint32_t rangeCount = selection->RangeCount();
+  if (rangeCount <= 0) {
+    return CaretMode::None;
+  }
+
+  if (selection->IsCollapsed()) {
+    return CaretMode::Cursor;
+  }
+
+  return CaretMode::Selection;
+}
+
+nsIFrame*
+AccessibleCaretManager::GetFocusableFrame(nsIFrame* aFrame) const
+{
+  // This implementation is similar to EventStateManager::PostHandleEvent().
+  // Look for the nearest enclosing focusable frame.
+  nsIFrame* focusableFrame = aFrame;
+  while (focusableFrame) {
+    if (focusableFrame->IsFocusable(nullptr, true)) {
+      break;
+    }
+    focusableFrame = focusableFrame->GetParent();
+  }
+  return focusableFrame;
+}
+
+void
+AccessibleCaretManager::ChangeFocusToOrClearOldFocus(nsIFrame* aFrame) const
+{
+  nsFocusManager* fm = nsFocusManager::GetFocusManager();
+  MOZ_ASSERT(fm);
+
+  if (aFrame) {
+    nsIContent* focusableContent = aFrame->GetContent();
+    MOZ_ASSERT(focusableContent, "Focusable frame must have content!");
+    nsCOMPtr<nsIDOMElement> focusableElement = do_QueryInterface(focusableContent);
+    fm->SetFocus(focusableElement, nsIFocusManager::FLAG_BYMOUSE);
+  } else {
+    nsPIDOMWindowOuter* win = mPresShell->GetDocument()->GetWindow();
+    if (win) {
+      fm->ClearFocus(win);
+      fm->SetFocusedWindow(win);
+    }
+  }
+}
+
+nsresult
+AccessibleCaretManager::SelectWord(nsIFrame* aFrame, const nsPoint& aPoint) const
+{
+  SetSelectionDragState(true);
+  nsFrame* frame = static_cast<nsFrame*>(aFrame);
+  nsresult rs = frame->SelectByTypeAtPoint(mPresShell->GetPresContext(), aPoint,
+                                           eSelectWord, eSelectWord, 0);
+
+  SetSelectionDragState(false);
+  ClearMaintainedSelection();
+
+  // Smart-select phone numbers if possible.
+  if (sExtendSelectionForPhoneNumber) {
+    SelectMoreIfPhoneNumber();
+  }
+
+  return rs;
+}
+
+void
+AccessibleCaretManager::SetSelectionDragState(bool aState) const
+{
+  RefPtr<nsFrameSelection> fs = GetFrameSelection();
+  if (fs) {
+    fs->SetDragState(aState);
+  }
+
+  // Pin Fennecs DynamicToolbarAnimator in place before/after dragging,
+  // to avoid co-incident screen scrolling.
+  #ifdef MOZ_WIDGET_ANDROID
+    nsIDocument* doc = mPresShell->GetDocument();
+    MOZ_ASSERT(doc);
+    nsIWidget* widget = nsContentUtils::WidgetForDocument(doc);
+    static_cast<nsWindow*>(widget)->SetSelectionDragState(aState);
+  #endif
+}
+
+void
+AccessibleCaretManager::SelectMoreIfPhoneNumber() const
+{
+  SetSelectionDirection(eDirNext);
+  ExtendPhoneNumberSelection(NS_LITERAL_STRING("forward"));
+
+  SetSelectionDirection(eDirPrevious);
+  ExtendPhoneNumberSelection(NS_LITERAL_STRING("backward"));
+
+  SetSelectionDirection(eDirNext);
+}
+
+void
+AccessibleCaretManager::ExtendPhoneNumberSelection(const nsAString& aDirection) const
+{
+  if (!mPresShell) {
+    return;
+  }
+
+  RefPtr<nsIDocument> doc = mPresShell->GetDocument();
+
+  // Extend the phone number selection until we find a boundary.
+  RefPtr<Selection> selection = GetSelection();
+
+  while (selection) {
+    const nsRange* anchorFocusRange = selection->GetAnchorFocusRange();
+    if (!anchorFocusRange) {
+      return;
+    }
+
+    // Backup the anchor focus range since both anchor node and focus node might
+    // be changed after calling Selection::Modify().
+    RefPtr<nsRange> oldAnchorFocusRange = anchorFocusRange->CloneRange();
+
+    // Save current Focus position, and extend the selection one char.
+    nsINode* focusNode = selection->GetFocusNode();
+    uint32_t focusOffset = selection->FocusOffset();
+    selection->Modify(NS_LITERAL_STRING("extend"),
+                      aDirection,
+                      NS_LITERAL_STRING("character"));
+    if (IsTerminated()) {
+      return;
+    }
+
+    // If the selection didn't change, (can't extend further), we're done.
+    if (selection->GetFocusNode() == focusNode &&
+        selection->FocusOffset() == focusOffset) {
+      return;
+    }
+
+    // If the changed selection isn't a valid phone number, we're done.
+    nsAutoString selectedText;
+    selection->Stringify(selectedText);
+    nsAutoString phoneRegex(NS_LITERAL_STRING("(^\\+)?[0-9\\s,\\-.()*#pw]{1,30}$"));
+
+    if (!nsContentUtils::IsPatternMatching(selectedText, phoneRegex, doc)) {
+      // Backout the undesired selection extend, restore the old anchor focus
+      // range before exit.
+      selection->SetAnchorFocusToRange(oldAnchorFocusRange);
+      return;
+    }
+  }
+}
+
+void
+AccessibleCaretManager::SetSelectionDirection(nsDirection aDir) const
+{
+  Selection* selection = GetSelection();
+  if (selection) {
+    selection->AdjustAnchorFocusForMultiRange(aDir);
+  }
+}
+
+void
+AccessibleCaretManager::ClearMaintainedSelection() const
+{
+  // Selection made by double-clicking for example will maintain the original
+  // word selection. We should clear it so that we can drag caret freely.
+  RefPtr<nsFrameSelection> fs = GetFrameSelection();
+  if (fs) {
+    fs->MaintainSelection(eSelectNoAmount);
+  }
+}
+
+void
+AccessibleCaretManager::FlushLayout() const
+{
+  if (mPresShell) {
+    mPresShell->FlushPendingNotifications(Flush_Layout);
+  }
+}
+
+nsIFrame*
+AccessibleCaretManager::GetFrameForFirstRangeStartOrLastRangeEnd(
+  nsDirection aDirection, int32_t* aOutOffset, nsINode** aOutNode,
+  int32_t* aOutNodeOffset) const
+{
+  if (!mPresShell) {
+    return nullptr;
+  }
+
+  MOZ_ASSERT(GetCaretMode() == CaretMode::Selection);
+  MOZ_ASSERT(aOutOffset, "aOutOffset shouldn't be nullptr!");
+
+  nsRange* range = nullptr;
+  RefPtr<nsINode> startNode;
+  RefPtr<nsINode> endNode;
+  int32_t nodeOffset = 0;
+  CaretAssociationHint hint;
+
+  RefPtr<Selection> selection = GetSelection();
+  bool findInFirstRangeStart = aDirection == eDirNext;
+
+  if (findInFirstRangeStart) {
+    range = selection->GetRangeAt(0);
+    startNode = range->GetStartParent();
+    endNode = range->GetEndParent();
+    nodeOffset = range->StartOffset();
+    hint = CARET_ASSOCIATE_AFTER;
+  } else {
+    range = selection->GetRangeAt(selection->RangeCount() - 1);
+    startNode = range->GetEndParent();
+    endNode = range->GetStartParent();
+    nodeOffset = range->EndOffset();
+    hint = CARET_ASSOCIATE_BEFORE;
+  }
+
+  nsCOMPtr<nsIContent> startContent = do_QueryInterface(startNode);
+  RefPtr<nsFrameSelection> fs = GetFrameSelection();
+  nsIFrame* startFrame =
+    fs->GetFrameForNodeOffset(startContent, nodeOffset, hint, aOutOffset);
+
+  if (!startFrame) {
+    ErrorResult err;
+    RefPtr<TreeWalker> walker = mPresShell->GetDocument()->CreateTreeWalker(
+      *startNode, nsIDOMNodeFilter::SHOW_ALL, nullptr, err);
+
+    if (!walker) {
+      return nullptr;
+    }
+
+    startFrame = startContent ? startContent->GetPrimaryFrame() : nullptr;
+    while (!startFrame && startNode != endNode) {
+      startNode = findInFirstRangeStart ? walker->NextNode(err)
+                                        : walker->PreviousNode(err);
+
+      if (!startNode) {
+        break;
+      }
+
+      startContent = startNode->AsContent();
+      startFrame = startContent ? startContent->GetPrimaryFrame() : nullptr;
+    }
+
+    // We are walking among the nodes in the content tree, so the node offset
+    // relative to startNode should be set to 0.
+    nodeOffset = 0;
+    *aOutOffset = 0;
+  }
+
+  if (startFrame) {
+    if (aOutNode) {
+      *aOutNode = startNode.get();
+    }
+    if (aOutNodeOffset) {
+      *aOutNodeOffset = nodeOffset;
+    }
+  }
+
+  return startFrame;
+}
+
+bool
+AccessibleCaretManager::RestrictCaretDraggingOffsets(
+  nsIFrame::ContentOffsets& aOffsets)
+{
+  if (!mPresShell) {
+    return false;
+  }
+
+  MOZ_ASSERT(GetCaretMode() == CaretMode::Selection);
+
+  nsDirection dir = mActiveCaret == mFirstCaret.get() ? eDirPrevious : eDirNext;
+  int32_t offset = 0;
+  nsINode* node = nullptr;
+  int32_t contentOffset = 0;
+  nsIFrame* frame =
+    GetFrameForFirstRangeStartOrLastRangeEnd(dir, &offset, &node, &contentOffset);
+
+  if (!frame) {
+    return false;
+  }
+
+  nsCOMPtr<nsIContent> content = do_QueryInterface(node);
+
+  // Compare the active caret's new position (aOffsets) to the inactive caret's
+  // position.
+  int32_t cmpToInactiveCaretPos =
+    nsContentUtils::ComparePoints(aOffsets.content, aOffsets.StartOffset(),
+                                  content, contentOffset);
+
+  // Move one character (in the direction of dir) from the inactive caret's
+  // position. This is the limit for the active caret's new position.
+  nsPeekOffsetStruct limit(eSelectCluster, dir, offset, nsPoint(0, 0), true, true,
+                           false, false, false);
+  nsresult rv = frame->PeekOffset(&limit);
+  if (NS_FAILED(rv)) {
+    limit.mResultContent = content;
+    limit.mContentOffset = contentOffset;
+  }
+
+  // Compare the active caret's new position (aOffsets) to the limit.
+  int32_t cmpToLimit =
+    nsContentUtils::ComparePoints(aOffsets.content, aOffsets.StartOffset(),
+                                  limit.mResultContent, limit.mContentOffset);
+
+  auto SetOffsetsToLimit = [&aOffsets, &limit] () {
+    aOffsets.content = limit.mResultContent;
+    aOffsets.offset = limit.mContentOffset;
+    aOffsets.secondaryOffset = limit.mContentOffset;
+  };
+
+  if (!sCaretsAllowDraggingAcrossOtherCaret) {
+    if ((mActiveCaret == mFirstCaret.get() && cmpToLimit == 1) ||
+        (mActiveCaret == mSecondCaret.get() && cmpToLimit == -1)) {
+      // The active caret's position is past the limit, which we don't allow
+      // here. So set it to the limit, resulting in one character being
+      // selected.
+      SetOffsetsToLimit();
+    }
+  } else {
+    switch (cmpToInactiveCaretPos) {
+      case 0:
+        // The active caret's position is the same as the position of the
+        // inactive caret. So set it to the limit to prevent the selection from
+        // being collapsed, resulting in one character being selected.
+        SetOffsetsToLimit();
+        break;
+      case 1:
+        if (mActiveCaret == mFirstCaret.get()) {
+          // First caret was moved across the second caret. After making change
+          // to the selection, the user will drag the second caret.
+          mActiveCaret = mSecondCaret.get();
+        }
+        break;
+      case -1:
+        if (mActiveCaret == mSecondCaret.get()) {
+          // Second caret was moved across the first caret. After making change
+          // to the selection, the user will drag the first caret.
+          mActiveCaret = mFirstCaret.get();
+        }
+        break;
+    }
+  }
+
+  return true;
+}
+
+bool
+AccessibleCaretManager::CompareTreePosition(nsIFrame* aStartFrame,
+                                            nsIFrame* aEndFrame) const
+{
+  return (aStartFrame && aEndFrame &&
+          nsLayoutUtils::CompareTreePosition(aStartFrame, aEndFrame) <= 0);
+}
+
+nsresult
+AccessibleCaretManager::DragCaretInternal(const nsPoint& aPoint)
+{
+  if (!mPresShell) {
+    return NS_ERROR_NULL_POINTER;
+  }
+
+  nsIFrame* rootFrame = mPresShell->GetRootFrame();
+  if (!rootFrame) {
+    return NS_ERROR_NULL_POINTER;
+  }
+
+  nsPoint point = AdjustDragBoundary(aPoint);
+
+  // Find out which content we point to
+  nsIFrame* ptFrame = nsLayoutUtils::GetFrameForPoint(
+    rootFrame, point,
+    nsLayoutUtils::IGNORE_PAINT_SUPPRESSION | nsLayoutUtils::IGNORE_CROSS_DOC);
+  if (!ptFrame) {
+    return NS_ERROR_FAILURE;
+  }
+
+  RefPtr<nsFrameSelection> fs = GetFrameSelection();
+  if (!fs) {
+    return NS_ERROR_NULL_POINTER;
+  }
+
+  nsresult result;
+  nsIFrame* newFrame = nullptr;
+  nsPoint newPoint;
+  nsPoint ptInFrame = point;
+  nsLayoutUtils::TransformPoint(rootFrame, ptFrame, ptInFrame);
+  result = fs->ConstrainFrameAndPointToAnchorSubtree(ptFrame, ptInFrame,
+                                                     &newFrame, newPoint);
+  if (NS_FAILED(result) || !newFrame) {
+    return NS_ERROR_FAILURE;
+  }
+
+  bool selectable;
+  newFrame->IsSelectable(&selectable, nullptr);
+  if (!selectable) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsIFrame::ContentOffsets offsets =
+    newFrame->GetContentOffsetsFromPoint(newPoint);
+  if (offsets.IsNull()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  Selection* selection = GetSelection();
+  if (!selection) {
+    return NS_ERROR_NULL_POINTER;
+  }
+
+  if (GetCaretMode() == CaretMode::Selection &&
+      !RestrictCaretDraggingOffsets(offsets)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  ClearMaintainedSelection();
+
+  nsIFrame* anchorFrame = nullptr;
+  selection->GetPrimaryFrameForAnchorNode(&anchorFrame);
+
+  nsIFrame* scrollable =
+    nsLayoutUtils::GetClosestFrameOfType(anchorFrame, nsGkAtoms::scrollFrame);
+  nsWeakFrame weakScrollable = scrollable;
+  fs->HandleClick(offsets.content, offsets.StartOffset(), offsets.EndOffset(),
+                  GetCaretMode() == CaretMode::Selection, false,
+                  offsets.associate);
+  if (!weakScrollable.IsAlive()) {
+    return NS_OK;
+  }
+
+  // Scroll scrolled frame.
+  nsIScrollableFrame* saf = do_QueryFrame(scrollable);
+  nsIFrame* capturingFrame = saf->GetScrolledFrame();
+  nsPoint ptInScrolled = point;
+  nsLayoutUtils::TransformPoint(rootFrame, capturingFrame, ptInScrolled);
+  fs->StartAutoScrollTimer(capturingFrame, ptInScrolled, kAutoScrollTimerDelay);
+  return NS_OK;
+}
+
+nsRect
+AccessibleCaretManager::GetAllChildFrameRectsUnion(nsIFrame* aFrame) const
+{
+  nsRect unionRect;
+
+  // Drill through scroll frames, we don't want to include scrollbar child
+  // frames below.
+  for (nsIFrame* frame = aFrame->GetContentInsertionFrame();
+       frame;
+       frame = frame->GetNextContinuation()) {
+    nsRect frameRect;
+
+    for (nsIFrame::ChildListIterator lists(frame); !lists.IsDone(); lists.Next()) {
+      // Loop all children to union their scrollable overflow rect.
+      for (nsIFrame* child : lists.CurrentList()) {
+        nsRect childRect = child->GetScrollableOverflowRectRelativeToSelf();
+        nsLayoutUtils::TransformRect(child, frame, childRect);
+
+        // A TextFrame containing only '\n' has positive height and width 0, or
+        // positive width and height 0 if it's vertical. Need to use UnionEdges
+        // to add its rect. BRFrame rect should be non-empty.
+        if (childRect.IsEmpty()) {
+          frameRect = frameRect.UnionEdges(childRect);
+        } else {
+          frameRect = frameRect.Union(childRect);
+        }
+      }
+    }
+
+    MOZ_ASSERT(!frameRect.IsEmpty(),
+               "Editable frames should have at least one BRFrame child to make "
+               "frameRect non-empty!");
+    if (frame != aFrame) {
+      nsLayoutUtils::TransformRect(frame, aFrame, frameRect);
+    }
+    unionRect = unionRect.Union(frameRect);
+  }
+
+  return unionRect;
+}
+
+nsPoint
+AccessibleCaretManager::AdjustDragBoundary(const nsPoint& aPoint) const
+{
+  nsPoint adjustedPoint = aPoint;
+
+  int32_t focusOffset = 0;
+  nsIFrame* focusFrame =
+    nsCaret::GetFrameAndOffset(GetSelection(), nullptr, 0, &focusOffset);
+  Element* editingHost = GetEditingHostForFrame(focusFrame);
+
+  if (editingHost) {
+    nsIFrame* editingHostFrame = editingHost->GetPrimaryFrame();
+    if (editingHostFrame) {
+      nsRect boundary = GetAllChildFrameRectsUnion(editingHostFrame);
+      nsLayoutUtils::TransformRect(editingHostFrame, mPresShell->GetRootFrame(),
+                                   boundary);
+
+      // Shrink the rect to make sure we never hit the boundary.
+      boundary.Deflate(kBoundaryAppUnits);
+
+      adjustedPoint = boundary.ClampPoint(adjustedPoint);
+    }
+  }
+
+  if (GetCaretMode() == CaretMode::Selection &&
+      !sCaretsAllowDraggingAcrossOtherCaret) {
+    // Bug 1068474: Adjust the Y-coordinate so that the carets won't be in tilt
+    // mode when a caret is being dragged surpass the other caret.
+    //
+    // For example, when dragging the second caret, the horizontal boundary (lower
+    // bound) of its Y-coordinate is the logical position of the first caret.
+    // Likewise, when dragging the first caret, the horizontal boundary (upper
+    // bound) of its Y-coordinate is the logical position of the second caret.
+    if (mActiveCaret == mFirstCaret.get()) {
+      nscoord dragDownBoundaryY = mSecondCaret->LogicalPosition().y;
+      if (dragDownBoundaryY > 0 && adjustedPoint.y > dragDownBoundaryY) {
+        adjustedPoint.y = dragDownBoundaryY;
+      }
+    } else {
+      nscoord dragUpBoundaryY = mFirstCaret->LogicalPosition().y;
+      if (adjustedPoint.y < dragUpBoundaryY) {
+        adjustedPoint.y = dragUpBoundaryY;
+      }
+    }
+  }
+
+  return adjustedPoint;
+}
+
+uint32_t
+AccessibleCaretManager::CaretTimeoutMs() const
+{
+  static bool added = false;
+  static uint32_t caretTimeoutMs = 0;
+
+  if (!added) {
+    Preferences::AddUintVarCache(&caretTimeoutMs,
+                                 "layout.accessiblecaret.timeout_ms");
+    added = true;
+  }
+
+  return caretTimeoutMs;
+}
+
+void
+AccessibleCaretManager::LaunchCaretTimeoutTimer()
+{
+  if (!mPresShell || !mCaretTimeoutTimer || CaretTimeoutMs() == 0 ||
+      GetCaretMode() != CaretMode::Cursor || mActiveCaret) {
+    return;
+  }
+
+  nsTimerCallbackFunc callback = [](nsITimer* aTimer, void* aClosure) {
+    auto self = static_cast<AccessibleCaretManager*>(aClosure);
+    if (self->GetCaretMode() == CaretMode::Cursor) {
+      self->HideCarets();
+    }
+  };
+
+  mCaretTimeoutTimer->InitWithFuncCallback(callback, this, CaretTimeoutMs(),
+                                           nsITimer::TYPE_ONE_SHOT);
+}
+
+void
+AccessibleCaretManager::CancelCaretTimeoutTimer()
+{
+  if (mCaretTimeoutTimer) {
+    mCaretTimeoutTimer->Cancel();
+  }
+}
+
+void
+AccessibleCaretManager::DispatchCaretStateChangedEvent(CaretChangedReason aReason) const
+{
+  if (!mPresShell) {
+    return;
+  }
+
+  FlushLayout();
+  if (IsTerminated()) {
+    return;
+  }
+
+  Selection* sel = GetSelection();
+  if (!sel) {
+    return;
+  }
+
+  nsIDocument* doc = mPresShell->GetDocument();
+  MOZ_ASSERT(doc);
+
+  CaretStateChangedEventInit init;
+  init.mBubbles = true;
+
+  const nsRange* range = sel->GetAnchorFocusRange();
+  nsINode* commonAncestorNode = nullptr;
+  if (range) {
+    commonAncestorNode = range->GetCommonAncestor();
+  }
+
+  if (!commonAncestorNode) {
+    commonAncestorNode = sel->GetFrameSelection()->GetAncestorLimiter();
+  }
+
+  RefPtr<DOMRect> domRect = new DOMRect(ToSupports(doc));
+  nsRect rect = nsLayoutUtils::GetSelectionBoundingRect(sel);
+
+  nsIFrame* commonAncestorFrame = nullptr;
+  nsIFrame* rootFrame = mPresShell->GetRootFrame();
+
+  if (commonAncestorNode && commonAncestorNode->IsContent()) {
+    commonAncestorFrame = commonAncestorNode->AsContent()->GetPrimaryFrame();
+  }
+
+  if (commonAncestorFrame && rootFrame) {
+    nsLayoutUtils::TransformRect(rootFrame, commonAncestorFrame, rect);
+    nsRect clampedRect = nsLayoutUtils::ClampRectToScrollFrames(commonAncestorFrame,
+                                                                rect);
+    nsLayoutUtils::TransformRect(commonAncestorFrame, rootFrame, clampedRect);
+    domRect->SetLayoutRect(clampedRect);
+    init.mSelectionVisible = !clampedRect.IsEmpty();
+  } else {
+    domRect->SetLayoutRect(rect);
+    init.mSelectionVisible = true;
+  }
+
+  // Send isEditable info w/ event detail. This info can help determine
+  // whether to show cut command on selection dialog or not.
+  init.mSelectionEditable = commonAncestorFrame &&
+    GetEditingHostForFrame(commonAncestorFrame);
+
+  init.mBoundingClientRect = domRect;
+  init.mReason = aReason;
+  init.mCollapsed = sel->IsCollapsed();
+  init.mCaretVisible = mFirstCaret->IsLogicallyVisible() ||
+                       mSecondCaret->IsLogicallyVisible();
+  init.mCaretVisuallyVisible = mFirstCaret->IsVisuallyVisible() ||
+                                mSecondCaret->IsVisuallyVisible();
+  sel->Stringify(init.mSelectedTextContent);
+
+  RefPtr<CaretStateChangedEvent> event =
+    CaretStateChangedEvent::Constructor(doc, NS_LITERAL_STRING("mozcaretstatechanged"), init);
+
+  event->SetTrusted(true);
+  event->WidgetEventPtr()->mFlags.mOnlyChromeDispatch = true;
+
+  AC_LOG("%s: reason %d, collapsed %d, caretVisible %d", __FUNCTION__,
+         init.mReason, init.mCollapsed, init.mCaretVisible);
+
+  (new AsyncEventDispatcher(doc, event))->RunDOMEventWhenSafe();
+}
+
+} // namespace mozilla