Oilpan: add [WillBeGarbageCollected] for Element.

Source/bindings/v8/custom/V8HTMLAllCollectionCustom.cpp

Index: Source/bindings/v8/custom/V8HTMLAllCollectionCustom.cpp
diff --git a/Source/bindings/v8/custom/V8HTMLAllCollectionCustom.cpp b/Source/bindings/v8/custom/V8HTMLAllCollectionCustom.cpp
index c93451e761b93f1b3993f3ef28c5154ce1612ba9..9c5be5f0cb311a3c538da96b84c4d92488f40768 100644
--- a/Source/bindings/v8/custom/V8HTMLAllCollectionCustom.cpp
+++ b/Source/bindings/v8/custom/V8HTMLAllCollectionCustom.cpp
@@ -71,7 +71,7 @@ static v8::Handle<v8::Value> getItem(HTMLAllCollection* collection, v8::Handle<v
         return result;
     }
 
-    RefPtr<Element> result = collection->item(index->Uint32Value());
+    RefPtrWillBeRawPtr<Element> result = collection->item(index->Uint32Value());
     return toV8(result.release(), info.Holder(), info.GetIsolate());
 }