Oilpan: move SVG property hierarchy to the heap.

Source/core/svg/SVGClipPathElement.h

Index: Source/core/svg/SVGClipPathElement.h
diff --git a/Source/core/svg/SVGClipPathElement.h b/Source/core/svg/SVGClipPathElement.h
index 1ccca60774bb08348de70c29739215cbd10bf25e..75954051d792b9c634b08c2357b473d892a7f848 100644
--- a/Source/core/svg/SVGClipPathElement.h
+++ b/Source/core/svg/SVGClipPathElement.h
@@ -26,6 +26,7 @@
 #include "core/svg/SVGAnimatedEnumeration.h"
 #include "core/svg/SVGGraphicsElement.h"
 #include "core/svg/SVGUnitTypes.h"
+#include "platform/heap/Handle.h"
 
 namespace blink {
 
@@ -39,6 +40,8 @@ public:
 
     virtual bool supportsFocus() const override { return false; }
 
+    virtual void trace(Visitor*) override;
+
 private:
     explicit SVGClipPathElement(Document&);
 
@@ -50,7 +53,7 @@ private:
 
     virtual RenderObject* createRenderer(RenderStyle*) override;
 
-    RefPtr<SVGAnimatedEnumeration<SVGUnitTypes::SVGUnitType> > m_clipPathUnits;
+    RefPtrWillBeMember<SVGAnimatedEnumeration<SVGUnitTypes::SVGUnitType> > m_clipPathUnits;
 };
 
 } // namespace blink