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

Source/WebCore/rendering/RenderObject.cpp

Index: Source/WebCore/rendering/RenderObject.cpp
===================================================================
--- Source/WebCore/rendering/RenderObject.cpp	(revision 146890)
+++ Source/WebCore/rendering/RenderObject.cpp	(working copy)
@@ -1865,10 +1865,8 @@
             if (visibilityChanged)
                 document()->setAnnotatedRegionsDirty(true);
 #endif
-            if (visibilityChanged) {
-                if (AXObjectCache* cache = document()->existingAXObjectCache())
-                    cache->childrenChanged(parent());
-            }
+            if (visibilityChanged && AXObjectCache::accessibilityEnabled())
+                document()->axObjectCache()->childrenChanged(parent());
 
             // Keep layer hierarchy visibility bits up to date if visibility changes.
             if (m_style->visibility() != newStyle->visibility()) {
@@ -2411,15 +2409,15 @@
 
     // For accessibility management, notify the parent of the imminent change to its child set.
     // We do it now, before remove(), while the parent pointer is still available.
-    if (AXObjectCache* cache = document()->existingAXObjectCache())
-        cache->childrenChanged(this->parent());
+    if (AXObjectCache::accessibilityEnabled())
+        document()->axObjectCache()->childrenChanged(this->parent());
 
     remove();
 
     // The remove() call above may invoke axObjectCache()->childrenChanged() on the parent, which may require the AX render
     // object for this renderer. So we remove the AX render object now, after the renderer is removed.
-    if (AXObjectCache* cache = document()->existingAXObjectCache())
-        cache->remove(this);
+    if (AXObjectCache::accessibilityEnabled())
+        document()->axObjectCache()->remove(this);
 
 #ifndef NDEBUG
     if (!documentBeingDestroyed() && view() && view()->hasRenderNamedFlowThreads()) {