Revert 146726 "AXObjectCache gets recreated during document tear..."

Source/WebCore/dom/Document.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
@@ skipping 541 matching lines @@
     RenderView* renderView() const;
 
     // Shadow the implementations on Node to provide faster access for documents.
     RenderObject* renderer() const { return m_renderer; }
     void setRenderer(RenderObject* renderer)
     {
         m_renderer = renderer;
         Node::setRenderer(renderer);
     }
 
-    AXObjectCache* existingAXObjectCache() const;
+    void clearAXObjectCache();
     AXObjectCache* axObjectCache() const;
-    void clearAXObjectCache();
-
+    bool axObjectCacheExists() const;
+    
     // to get visually ordered hebrew and arabic pages right
     void setVisuallyOrdered();
     bool visuallyOrdered() const { return m_visuallyOrdered; }
     
     DocumentLoader* loader() const;
 
     void open(Document* ownerDocument = 0);
     void implicitOpen();
 
     // close() is the DOM API document.close()
@@ skipping 1093 matching lines @@
     trackForDebugging();
 #endif
     InspectorCounters::incrementCounter(InspectorCounters::NodeCounter);
 }
 
 Node* eventTargetNodeForDocument(Document*);
 
 } // namespace WebCore
 
 #endif // Document_h