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

Source/WebCore/platform/Scrollbar.cpp

Index: Source/WebCore/platform/Scrollbar.cpp
===================================================================
--- Source/WebCore/platform/Scrollbar.cpp	(revision 146890)
+++ Source/WebCore/platform/Scrollbar.cpp	(working copy)
@@ -110,8 +110,8 @@
 
 Scrollbar::~Scrollbar()
 {
-    if (AXObjectCache* cache = existingAXObjectCache())
-        cache->remove(this);
+    if (AXObjectCache::accessibilityEnabled() && axObjectCache())
+        axObjectCache()->remove(this);
     
     stopTimerIfNeeded();
     
@@ -566,13 +566,16 @@
 {
     return m_scrollableArea && m_scrollableArea->isActive();
 }
-
-AXObjectCache* Scrollbar::existingAXObjectCache() const
+    
+AXObjectCache* Scrollbar::axObjectCache() const
 {
-    if (!parent())
+    if (!parent() || !parent()->isFrameView())
         return 0;
     
-    return parent()->axObjectCache();
+    // FIXME: Accessing the FrameView and Document here is a layering violation
+    // and should be removed.
+    Document* document = toFrameView(parent())->frame()->document();
+    return document->axObjectCache();
 }
 
 void Scrollbar::invalidateRect(const IntRect& rect)