Fix leaking AXNodeObjects when sub document detaches

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

 /*
  * Copyright (C) 2011 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 153 matching lines @@
         return false;
 
     if (ignoredReasons)
         return webArea->computeAccessibilityIsIgnored(ignoredReasons);
 
     return true;
 }
 
 void AXScrollView::addChildren()
 {
+    ASSERT(!isDetached());
     ASSERT(!m_haveChildren);
     m_haveChildren = true;
 
     AXObject* webArea = webAreaObject();
     if (webArea && !webArea->accessibilityIsIgnored())
         m_children.append(webArea);
 
     updateScrollbars();
 }
 
@@ skipping 34 matching lines @@
 FrameView* AXScrollView::documentFrameView() const
 {
     if (!m_scrollView || !m_scrollView->isFrameView())
         return 0;
 
     return m_scrollView;
 }
 
 AXObject* AXScrollView::computeParent() const
 {
+    ASSERT(!isDetached());
     if (!m_scrollView || !m_scrollView->isFrameView())
         return 0;
 
     // FIXME: Broken for OOPI.
     HTMLFrameOwnerElement* owner = m_scrollView->frame().deprecatedLocalOwner();
     if (owner && owner->layoutObject())
         return axObjectCache().getOrCreate(owner);
 
     return axObjectCache().getOrCreate(m_scrollView->frame().pagePopupOwner());
 }
@@ skipping 17 matching lines @@
 
 DEFINE_TRACE(AXScrollView)
 {
     visitor->trace(m_scrollView);
     visitor->trace(m_horizontalScrollbar);
     visitor->trace(m_verticalScrollbar);
     AXObject::trace(visitor);
 }
 
 } // namespace blink