Prepare SVGElement references in Document for oilpan

Source/core/dom/Document.h

Index: Source/core/dom/Document.h
diff --git a/Source/core/dom/Document.h b/Source/core/dom/Document.h
index 3bb563310a5060d65c17d754a97c7798218e964d..d101efbeb92b4ea4c5daa1f5dce47b238749c8e3 100644
--- a/Source/core/dom/Document.h
+++ b/Source/core/dom/Document.h
@@ -1413,8 +1413,8 @@ private:
     Timer<Document> m_didAssociateFormControlsTimer;
     WillBeHeapHashSet<RefPtrWillBeMember<Element> > m_associatedFormControls;
 
-    HashSet<SVGUseElement*> m_useElementsNeedingUpdate;
-    HashSet<Element*> m_layerUpdateSVGFilterElements;
+    WillBeHeapHashSet<RawPtrWillBeMember<SVGUseElement> > m_useElementsNeedingUpdate;
+    WillBeHeapHashSet<RawPtrWillBeMember<Element> > m_layerUpdateSVGFilterElements;

[haraken, 2014/06/17 01:09:29]

These elements are guaranteed to exist in the same tree, so it makes sense to
use strong pointers. Makes sense.

 
     bool m_hasViewportUnits;