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

Source/WebCore/rendering/RenderMenuList.cpp

 /*
  * This file is part of the select element renderer in WebCore.
  *
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  *               2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * 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
@@ skipping 124 matching lines @@
 {
     return toHTMLSelectElement(node());
 }
 
 void RenderMenuList::addChild(RenderObject* newChild, RenderObject* beforeChild)
 {
     createInnerBlock();
     m_innerBlock->addChild(newChild, beforeChild);
     ASSERT(m_innerBlock == firstChild());
 
-    if (AXObjectCache* cache = document()->existingAXObjectCache())
-        cache->childrenChanged(this);
+    if (AXObjectCache::accessibilityEnabled())
+        document()->axObjectCache()->childrenChanged(this);
 }
 
 void RenderMenuList::removeChild(RenderObject* oldChild)
 {
     if (oldChild == m_innerBlock || !m_innerBlock) {
         RenderFlexibleBox::removeChild(oldChild);
         m_innerBlock = 0;
     } else
         m_innerBlock->removeChild(oldChild);
 }
@@ skipping 214 matching lines @@
     return selectElement()->multiple();
 }
 
 void RenderMenuList::didSetSelectedIndex(int listIndex)
 {
     didUpdateActiveOption(selectElement()->listToOptionIndex(listIndex));
 }
 
 void RenderMenuList::didUpdateActiveOption(int optionIndex)
 {
-    if (!AXObjectCache::accessibilityEnabled() || !document()->existingAXObjectCache())
+    if (!AXObjectCache::accessibilityEnabled())
         return;
 
     if (m_lastActiveIndex == optionIndex)
         return;
     m_lastActiveIndex = optionIndex;
 
     HTMLSelectElement* select = selectElement();
     int listIndex = select->optionToListIndex(optionIndex);
     if (listIndex < 0 || listIndex >= static_cast<int>(select->listItems().size()))
         return;
@@ skipping 220 matching lines @@
 {
     setTextFromOption(selectElement()->listToOptionIndex(listIndex));
 }
 
 FontSelector* RenderMenuList::fontSelector() const
 {
     return document()->styleResolver()->fontSelector();
 }
 
 }