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

Source/WebCore/page/FocusController.cpp

Index: Source/WebCore/page/FocusController.cpp
===================================================================
--- Source/WebCore/page/FocusController.cpp	(revision 146890)
+++ Source/WebCore/page/FocusController.cpp	(working copy)
@@ -253,8 +253,8 @@
     // If focus is being set initially, accessibility needs to be informed that system focus has moved 
     // into the web area again, even if focus did not change within WebCore. PostNotification is called instead
     // of handleFocusedUIElementChanged, because this will send the notification even if the element is the same.
-    if (AXObjectCache* cache = focusedOrMainFrame()->document()->existingAXObjectCache())
-        cache->postNotification(focusedOrMainFrame()->document(), AXObjectCache::AXFocusedUIElementChanged, true);
+    if (AXObjectCache::accessibilityEnabled())
+        focusedOrMainFrame()->document()->axObjectCache()->postNotification(focusedOrMainFrame()->document(), AXObjectCache::AXFocusedUIElementChanged, true);
 
     return didAdvanceFocus;
 }