Oilpan: move SVG property hierarchy to the heap.

Source/core/svg/SVGAnimateElement.h

Index: Source/core/svg/SVGAnimateElement.h
diff --git a/Source/core/svg/SVGAnimateElement.h b/Source/core/svg/SVGAnimateElement.h
index e558f53975f27a74f8b353b0bf25c9b1b440d716..940af824e2be8e1eb9a39e947d690c3414291ab7 100644
--- a/Source/core/svg/SVGAnimateElement.h
+++ b/Source/core/svg/SVGAnimateElement.h
@@ -26,6 +26,7 @@
 #include "core/SVGNames.h"
 #include "core/svg/SVGAnimatedTypeAnimator.h"
 #include "core/svg/SVGAnimationElement.h"
+#include "platform/heap/Handle.h"
 #include "wtf/OwnPtr.h"
 
 namespace blink {
@@ -66,10 +67,10 @@ private:
 
     virtual bool hasValidAttributeType() override;
 
-    RefPtr<SVGPropertyBase> m_fromProperty;
-    RefPtr<SVGPropertyBase> m_toProperty;
-    RefPtr<SVGPropertyBase> m_toAtEndOfDurationProperty;
-    RefPtr<SVGPropertyBase> m_animatedProperty;
+    RefPtrWillBeMember<SVGPropertyBase> m_fromProperty;
+    RefPtrWillBeMember<SVGPropertyBase> m_toProperty;
+    RefPtrWillBeMember<SVGPropertyBase> m_toAtEndOfDurationProperty;
+    RefPtrWillBeMember<SVGPropertyBase> m_animatedProperty;
 
     OwnPtrWillBeMember<SVGAnimatedTypeAnimator> m_animator;
 };