Oilpan: cleanup based on review comments after removal of TreeShared.

Source/core/svg/SVGElement.h

 /*
  * Copyright (C) 2004, 2005, 2006, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006 Rob Buis <buis@kde.org>
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 90 matching lines @@
     void sendSVGLoadEventIfPossible(bool sendParentLoadEvents = false);
     void sendSVGLoadEventIfPossibleAsynchronously();
     void svgLoadEventTimerFired(Timer<SVGElement>*);
     virtual Timer<SVGElement>* svgLoadEventTimer();
 
     virtual AffineTransform* supplementalTransform() { return 0; }
 
     void invalidateSVGAttributes() { ensureUniqueElementData().m_animatedSVGAttributesAreDirty = true; }
     void invalidateSVGPresentationAttributeStyle() { ensureUniqueElementData().m_presentationAttributeStyleIsDirty = true; }
 
-    const HashSet<SVGElement*>& instancesForElement() const;
+    const WillBeHeapHashSet<RawPtrWillBeWeakMember<SVGElement> >& instancesForElement() const;
 
     bool getBoundingBox(FloatRect&);
 
     void setCursorElement(SVGCursorElement*);
     void setCursorImageValue(CSSCursorImageValue*);
 #if !ENABLE(OILPAN)
     void cursorElementRemoved();
     void cursorImageValueRemoved();
 #endif
 
@@ skipping 131 matching lines @@
     static bool equal(const QualifiedName& a, const QualifiedName& b) { return a.matches(b); }
 };
 
 DEFINE_ELEMENT_TYPE_CASTS(SVGElement, isSVGElement());
 
 template <> inline bool isElementOfType<const SVGElement>(const Node& node) { return node.isSVGElement(); }
 
 }
 
 #endif