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 00c44a98ac8c111288dd7253400206006b5efb07..39f5552c8175d5ecad50e57ee68f3450898e0863 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> activeAnimations;
+    OwnPtrWillBeMember<ActiveAnimations> activeAnimations;
 };
 
 CSSStyleDeclaration& ElementRareData::ensureInlineCSSStyleDeclaration(Element* ownerElement)
@@ -49,6 +49,13 @@ CSSStyleDeclaration& ElementRareData::ensureInlineCSSStyleDeclaration(Element* o
     return *m_cssomWrapper;
 }
 
+void ElementRareData::traceAfterDispatch(Visitor* visitor)
+{
+    visitor->trace(m_shadow);
+    visitor->trace(m_cssomWrapper);
+    visitor->trace(m_activeAnimations);
+    NodeRareData::traceAfterDispatch(visitor);
+}
 
 COMPILE_ASSERT(sizeof(ElementRareData) == sizeof(SameSizeAsElementRareData), ElementRareDataShouldStaySmall);