Make FrameCaret to utilize SynchronousMutationObserver

third_party/WebKit/Source/core/editing/FrameCaret.cpp

 /*
  * Copyright (C) 2004, 2008, 2009, 2010 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 48 matching lines @@
       m_isCaretBlinkingSuspended(false),
       m_shouldShowBlockCursor(false) {}
 
 FrameCaret::~FrameCaret() = default;
 
 DEFINE_TRACE(FrameCaret) {
   visitor->trace(m_selectionEditor);
   visitor->trace(m_frame);
   visitor->trace(m_previousCaretNode);
   visitor->trace(m_previousCaretAnchorNode);
+  SynchronousMutationObserver::trace(visitor);
+}
+
+void FrameCaret::documentAttached(Document* document) {
+  setContext(document);
 }
 
 const PositionWithAffinity FrameCaret::caretPosition() const {
   const VisibleSelection& selection =
       m_selectionEditor->visibleSelection<EditingStrategy>();
   if (!selection.isCaret())
     return PositionWithAffinity();
   return PositionWithAffinity(selection.start(), selection.affinity());
 }
 
@@ skipping 216 matching lines @@
   // Hits in ManualTests/caret-paint-after-last-text-is-removed.html
   DisableCompositingQueryAsserts disabler;
   m_caretBase->invalidateLocalCaretRect(m_previousCaretAnchorNode.get(),
                                         m_previousCaretRect);
   m_previousCaretNode = nullptr;
   m_previousCaretAnchorNode = nullptr;
   m_previousCaretRect = LayoutRect();
   m_previousCaretVisibility = CaretVisibility::Hidden;
 }
 
-void FrameCaret::documentDetached() {
+void FrameCaret::contextDestroyed(Document*) {
   m_caretBlinkTimer.stop();
   m_previousCaretNode.clear();
   m_previousCaretAnchorNode.clear();
 }
 
 bool FrameCaret::shouldBlinkCaret() const {
   if (m_caretVisibility != CaretVisibility::Visible || !isActive())
     return false;
 
   Element* root = rootEditableElementOf(caretPosition().position());
@@ skipping 10 matching lines @@
 
 void FrameCaret::caretBlinkTimerFired(TimerBase*) {
   DCHECK_EQ(m_caretVisibility, CaretVisibility::Visible);
   if (isCaretBlinkingSuspended() && m_shouldPaintCaret)
     return;
   m_shouldPaintCaret = !m_shouldPaintCaret;
   setCaretRectNeedsUpdate();
 }
 
 }  // namespace blink