Oilpan: move node/element rare data objects to the heap.

Source/core/dom/ElementRareData.cpp

Index: Source/core/dom/ElementRareData.cpp
diff --git a/Source/core/dom/ElementRareData.cpp b/Source/core/dom/ElementRareData.cpp
index 42d508343a0e7e2fb97e03a468eb3f750b63fcf5..f969d8c62e0810f6780885ce2fe9d05272957432 100644
--- a/Source/core/dom/ElementRareData.cpp
+++ b/Source/core/dom/ElementRareData.cpp
@@ -40,7 +40,7 @@ struct SameSizeAsElementRareData : NodeRareData {
     LayoutSize sizeForResizing;
     IntSize scrollOffset;
     void* pointers[11];
-    OwnPtrWillBePersistent<ActiveAnimations> m_activeAnimations;
+    OwnPtrWillBeMember<ActiveAnimations> m_activeAnimations;
 };
 
 CSSStyleDeclaration& ElementRareData::ensureInlineCSSStyleDeclaration(Element* ownerElement)
@@ -50,6 +50,11 @@ CSSStyleDeclaration& ElementRareData::ensureInlineCSSStyleDeclaration(Element* o
     return *m_cssomWrapper;
 }
 
+void ElementRareData::traceAfterDispatch(Visitor* visitor)
+{
+    visitor->trace(m_activeAnimations);
+    NodeRareData::traceAfterDispatch(visitor);
+}
 
 COMPILE_ASSERT(sizeof(ElementRareData) == sizeof(SameSizeAsElementRareData), ElementRareDataShouldStaySmall);