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 37f9430b144f794f3665a523ccc4b61fb8a89069..e047453bc0b5ea49bcf2ce5c88f8263bdf07b1a7 100644
--- a/Source/core/dom/ElementRareData.cpp
+++ b/Source/core/dom/ElementRareData.cpp
@@ -39,7 +39,7 @@ struct SameSizeAsElementRareData : NodeRareData {
     short indices[2];
     IntSize scrollOffset;
     void* pointers[11];
-    OwnPtrWillBePersistent<ActiveAnimations> m_activeAnimations;
+    OwnPtrWillBeMember<ActiveAnimations> m_activeAnimations;
 };
 
 CSSStyleDeclaration& ElementRareData::ensureInlineCSSStyleDeclaration(Element* ownerElement)
@@ -49,6 +49,12 @@ CSSStyleDeclaration& ElementRareData::ensureInlineCSSStyleDeclaration(Element* o
     return *m_cssomWrapper;
 }
 
+void ElementRareData::traceAfterDispatch(Visitor* visitor)
+{
+    visitor->trace(m_shadow);
+    visitor->trace(m_activeAnimations);
+    NodeRareData::traceAfterDispatch(visitor);
+}
 
 COMPILE_ASSERT(sizeof(ElementRareData) == sizeof(SameSizeAsElementRareData), ElementRareDataShouldStaySmall);