Oilpan: move SVG property hierarchy to the heap.

Source/core/svg/SVGImageElement.h

Index: Source/core/svg/SVGImageElement.h
diff --git a/Source/core/svg/SVGImageElement.h b/Source/core/svg/SVGImageElement.h
index 6bd64712c16d2d232eaa4dd9cad62d83780d0b67..adf90a7941a99b98605a29852c27d75e0dbc30ac 100644
--- a/Source/core/svg/SVGImageElement.h
+++ b/Source/core/svg/SVGImageElement.h
@@ -28,12 +28,14 @@
 #include "core/svg/SVGGraphicsElement.h"
 #include "core/svg/SVGImageLoader.h"
 #include "core/svg/SVGURIReference.h"
+#include "platform/heap/Handle.h"
 
 namespace blink {
 
 class SVGImageElement final : public SVGGraphicsElement,
                               public SVGURIReference {
     DEFINE_WRAPPERTYPEINFO();
+    WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(SVGImageElement);
 public:
     DECLARE_NODE_FACTORY(SVGImageElement);
     virtual void trace(Visitor*) override;
@@ -70,11 +72,11 @@ private:
     virtual void didMoveToNewDocument(Document& oldDocument) override;
     SVGImageLoader& imageLoader() { return *m_imageLoader; }
 
-    RefPtr<SVGAnimatedLength> m_x;
-    RefPtr<SVGAnimatedLength> m_y;
-    RefPtr<SVGAnimatedLength> m_width;
-    RefPtr<SVGAnimatedLength> m_height;
-    RefPtr<SVGAnimatedPreserveAspectRatio> m_preserveAspectRatio;
+    RefPtrWillBeMember<SVGAnimatedLength> m_x;
+    RefPtrWillBeMember<SVGAnimatedLength> m_y;
+    RefPtrWillBeMember<SVGAnimatedLength> m_width;
+    RefPtrWillBeMember<SVGAnimatedLength> m_height;
+    RefPtrWillBeMember<SVGAnimatedPreserveAspectRatio> m_preserveAspectRatio;
 
     OwnPtrWillBeMember<SVGImageLoader> m_imageLoader;
     bool m_needsLoaderURIUpdate : 1;