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

Source/WebCore/platform/ScrollView.cpp

 /*
  * Copyright (C) 2006, 2007, 2008 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 81 matching lines @@
         m_horizontalScrollbar = createScrollbar(HorizontalScrollbar);
         addChild(m_horizontalScrollbar.get());
         didAddHorizontalScrollbar(m_horizontalScrollbar.get());
         m_horizontalScrollbar->styleChanged();
     } else if (!hasBar && m_horizontalScrollbar) {
         willRemoveHorizontalScrollbar(m_horizontalScrollbar.get());
         removeChild(m_horizontalScrollbar.get());
         m_horizontalScrollbar = 0;
     }
     
-    if (AXObjectCache* cache = axObjectCache())
-        cache->handleScrollbarUpdate(this);
+    if (AXObjectCache::accessibilityEnabled() && axObjectCache())
+        axObjectCache()->handleScrollbarUpdate(this);
 }
 
 void ScrollView::setHasVerticalScrollbar(bool hasBar)
 {
     ASSERT(!hasBar || !avoidScrollbarCreation());
     if (hasBar && !m_verticalScrollbar) {
         m_verticalScrollbar = createScrollbar(VerticalScrollbar);
         addChild(m_verticalScrollbar.get());
         didAddVerticalScrollbar(m_verticalScrollbar.get());
         m_verticalScrollbar->styleChanged();
     } else if (!hasBar && m_verticalScrollbar) {
         willRemoveVerticalScrollbar(m_verticalScrollbar.get());
         removeChild(m_verticalScrollbar.get());
         m_verticalScrollbar = 0;
     }
     
-    if (AXObjectCache* cache = axObjectCache())
-        cache->handleScrollbarUpdate(this);
+    if (AXObjectCache::accessibilityEnabled() && axObjectCache())
+        axObjectCache()->handleScrollbarUpdate(this);
 }
 
 #if !PLATFORM(GTK)
 PassRefPtr<Scrollbar> ScrollView::createScrollbar(ScrollbarOrientation orientation)
 {
     return Scrollbar::createNativeScrollbar(this, orientation, RegularScrollbar);
 }
 
 void ScrollView::setScrollbarModes(ScrollbarMode horizontalMode, ScrollbarMode verticalMode,
                                    bool horizontalLock, bool verticalLock)
@@ skipping 1296 matching lines @@
 }
 
 bool ScrollView::platformIsOffscreen() const
 {
     return false;
 }
 
 #endif
 
 }