Oilpan: Remove guardRef and guardDeref from TreeScope.

Source/core/accessibility/AXObjectCache.h

 /*
  * Copyright (C) 2003, 2006, 2007, 2008, 2009, 2010, 2011 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 90 matching lines @@
     AXObject* get(Widget*);
     AXObject* get(Node*);
     AXObject* get(AbstractInlineTextBox*);
 
     void remove(RenderObject*);
     void remove(Node*);
     void remove(Widget*);
     void remove(AbstractInlineTextBox*);
     void remove(AXID);
 
+    void clearWeakMembers(Visitor*);
+
     void detachWrapper(AXObject*);
     void attachWrapper(AXObject*);
     void childrenChanged(Node*);
     void childrenChanged(RenderObject*);
     void childrenChanged(AXObject*);
     void checkedStateChanged(Node*);
     void selectedChildrenChanged(Node*);
     void selectedChildrenChanged(RenderObject*);
     void selectionChanged(Node*);
     // Called by a node when text or a text equivalent (e.g. alt) attribute is changed.
@@ skipping 86 matching lines @@
     void removeNodeForUse(Node* n) { m_textMarkerNodes.remove(n); }
     bool isNodeInUse(Node* n) { return m_textMarkerNodes.contains(n); }
 
 private:
     Document& m_document;
     HashMap<AXID, RefPtr<AXObject> > m_objects;
     HashMap<RenderObject*, AXID> m_renderObjectMapping;
     HashMap<Widget*, AXID> m_widgetObjectMapping;
     HashMap<Node*, AXID> m_nodeObjectMapping;
     HashMap<AbstractInlineTextBox*, AXID> m_inlineTextBoxObjectMapping;
     HashSet<Node*> m_textMarkerNodes;

[Erik Corry, 2014/04/24 13:53:16]

I wonder who clears this out?

[Mads Ager (chromium), 2014/04/24 14:12:14]

clearWeakMembers does. This set is only used in the three methods above:
setNodeInUse, removeNodeForUse, isNodeInUse. They are only used from the  cpp
file. The node is removed in the method called |remove| which we call for all
dead nodes in the cache during weak processing.

     OwnPtr<AXComputedObjectAttributeCache> m_computedObjectAttributeCache;
     static bool gAccessibilityEnabled;
     static bool gInlineTextBoxAccessibility;
 
     HashSet<AXID> m_idsInUse;
 
     Timer<AXObjectCache> m_notificationPostTimer;
     Vector<pair<RefPtr<AXObject>, AXNotification> > m_notificationsToPost;
     void notificationPostTimerFired(Timer<AXObjectCache>*);
 
     static AXObject* focusedImageMapUIElement(HTMLAreaElement*);
 
     AXID getAXID(AXObject*);
 };
 
 bool nodeHasRole(Node*, const String& role);
 // This will let you know if aria-hidden was explicitly set to false.
 bool isNodeAriaVisible(Node*);
 
 }
 
 #endif