Enable DumpAccessibilityTree tests to use cross-process iframes.

third_party/WebKit/Source/modules/accessibility/AXLayoutObject.cpp

 /*
 * Copyright (C) 2008 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 216 matching lines @@
     // We want to notify that the combo box has changed its active descendant,
     // but we do not want to change the focus, because focus should remain with the combo box.
     if (isComboBox())
         return true;
 
     return shouldFocusActiveDescendant();
 }
 
 ScrollableArea* AXLayoutObject::getScrollableAreaIfScrollable() const
 {
-    // FIXME(dmazzoni): the plan is to get rid of AXScrollView, but until
-    // this is done, a WebArea delegates its scrolling to its parent scroll view.
-    // http://crbug.com/484878
-    if (parentObject() && parentObject()->isAXScrollView())
-        return parentObject()->getScrollableAreaIfScrollable();
+    if (isWebArea())
+        return documentFrameView();
 
     if (!m_layoutObject || !m_layoutObject->isBox())
         return 0;
 
     LayoutBox* box = toLayoutBox(m_layoutObject);
     if (!box->canBeScrolledAndHasScrollableArea())
         return 0;
 
     return box->scrollableArea();
 }
@@ skipping 2281 matching lines @@
         if (label && label->layoutObject()) {
             LayoutRect labelRect = axObjectCache().getOrCreate(label)->elementRect();
             result.unite(labelRect);
         }
     }
 
     return result;
 }
 
 } // namespace blink