Move Document pointer from Frame to LocalFrame.

Source/core/accessibility/AXObjectCache.cpp

Index: Source/core/accessibility/AXObjectCache.cpp
diff --git a/Source/core/accessibility/AXObjectCache.cpp b/Source/core/accessibility/AXObjectCache.cpp
index 48a98112347bd9e5c327add4183dbdb5e3cd9980..1435f528ffb487160fab0afa0b988158eebcf333 100644
--- a/Source/core/accessibility/AXObjectCache.cpp
+++ b/Source/core/accessibility/AXObjectCache.cpp
@@ -161,8 +161,12 @@ AXObject* AXObjectCache::focusedUIElementForPage(const Page* page)
     if (!gAccessibilityEnabled)
         return 0;
 
+    // Cross-process accessibility is not yet implemented.
+    if (!page->focusController().focusedOrMainFrame()->isLocalFrame())
+        return 0;
+
     // get the focused node in the page
-    Document* focusedDocument = page->focusController().focusedOrMainFrame()->document();
+    Document* focusedDocument = toLocalFrame(page->focusController().focusedOrMainFrame())->document();
     Node* focusedNode = focusedDocument->focusedElement();
     if (!focusedNode)
         focusedNode = focusedDocument;