Move the Widget hierarchy to the Oilpan heap.

Source/core/accessibility/AXScrollView.h

Index: Source/core/accessibility/AXScrollView.h
diff --git a/Source/core/accessibility/AXScrollView.h b/Source/core/accessibility/AXScrollView.h
index fbe205301e42f7ab1cda1d146f17dd49d697d7a0..2565ff7ef4862c90109273e85244a6e457fd562f 100644
--- a/Source/core/accessibility/AXScrollView.h
+++ b/Source/core/accessibility/AXScrollView.h
@@ -75,6 +75,11 @@ private:
     AXScrollbar* addChildScrollbar(Scrollbar*);
     void removeChildScrollbar(AXObject*);
 
+    // FIXME: Oilpan: Frame/ScrollView is on the heap, but can we
+    // assume that the corresponding AXScrollView is retired from
+    // the AX cache before it is finalized? If so, maintaining
+    // this as a bare pointer appears preferable. A persistent
+    // could create a leak.

[haraken, 2014/09/29 14:16:35]

Would you update this comment to clarify that using a raw pointer for
m_scrollView is fine because m_scrollView is explicitly cleared in
AXScrollView::detach() ?

[sof, 2014/10/08 11:52:25]

Thanks, clarified.

     ScrollView* m_scrollView;
     RefPtr<AXObject> m_horizontalScrollbar;
     RefPtr<AXObject> m_verticalScrollbar;