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

Source/WebCore/rendering/RenderMenuList.cpp

Index: Source/WebCore/rendering/RenderMenuList.cpp
===================================================================
--- Source/WebCore/rendering/RenderMenuList.cpp	(revision 146890)
+++ Source/WebCore/rendering/RenderMenuList.cpp	(working copy)
@@ -142,8 +142,8 @@
     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)
@@ -378,7 +378,7 @@
 
 void RenderMenuList::didUpdateActiveOption(int optionIndex)
 {
-    if (!AXObjectCache::accessibilityEnabled() || !document()->existingAXObjectCache())
+    if (!AXObjectCache::accessibilityEnabled())
         return;
 
     if (m_lastActiveIndex == optionIndex)