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

Source/WebCore/rendering/RenderWidget.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2006, 2009, 2010 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 84 matching lines @@
     , m_refCount(1)
 {
     view()->addWidget(this);
 }
 
 void RenderWidget::willBeDestroyed()
 {
     if (RenderView* v = view())
         v->removeWidget(this);
     
-    if (AXObjectCache* cache = document()->existingAXObjectCache()) {
-        cache->childrenChanged(this->parent());
-        cache->remove(this);
+    if (AXObjectCache::accessibilityEnabled()) {
+        document()->axObjectCache()->childrenChanged(this->parent());
+        document()->axObjectCache()->remove(this);
     }
 
     setWidget(0);
 
     RenderReplaced::willBeDestroyed();
 }
 
 void RenderWidget::destroy()
 {
     willBeDestroyed();
@@ skipping 286 matching lines @@
 CursorDirective RenderWidget::getCursor(const LayoutPoint& point, Cursor& cursor) const
 {
     if (widget() && widget()->isPluginViewBase()) {
         // A plug-in is responsible for setting the cursor when the pointer is over it.
         return DoNotSetCursor;
     }
     return RenderReplaced::getCursor(point, cursor);
 }
 
 } // namespace WebCore