Make IDL Callbacks non-refcounted by default

Source/bindings/v8/V8MutationCallback.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 13 matching lines @@
  */
 
 #ifndef V8MutationCallback_h
 #define V8MutationCallback_h
 
 #include "bindings/v8/ActiveDOMCallback.h"
 #include "bindings/v8/DOMWrapperWorld.h"
 #include "bindings/v8/ScopedPersistent.h"
 #include "bindings/v8/V8Utilities.h"
 #include "core/dom/MutationCallback.h"
+#include "wtf/OwnPtr.h"
+#include "wtf/RefPtr.h"
 #include <v8.h>
-#include "wtf/RefPtr.h"
 
 namespace WebCore {
 
 class ExecutionContext;
 
 class V8MutationCallback : public MutationCallback, public ActiveDOMCallback {
 public:
-    static PassRefPtr<V8MutationCallback> create(v8::Handle<v8::Function> callback, ExecutionContext* context, v8::Handle<v8::Object> owner, v8::Isolate* isolate)
+    static PassOwnPtr<V8MutationCallback> create(v8::Handle<v8::Function> callback, ExecutionContext* context, v8::Handle<v8::Object> owner, v8::Isolate* isolate)
     {
         ASSERT(context);
-        return adoptRef(new V8MutationCallback(callback, context, owner, isolate));
+        return adoptPtr(new V8MutationCallback(callback, context, owner, isolate));
     }
 
     virtual void call(const Vector<RefPtr<MutationRecord> >&, MutationObserver*) OVERRIDE;
     virtual ExecutionContext* executionContext() const OVERRIDE { return ContextLifecycleObserver::executionContext(); }
 
 private:
     V8MutationCallback(v8::Handle<v8::Function>, ExecutionContext*, v8::Handle<v8::Object>, v8::Isolate*);
 
     static void makeWeakCallback(v8::Isolate*, v8::Persistent<v8::Function>*, V8MutationCallback*);
 
     ScopedPersistent<v8::Function> m_callback;
     RefPtr<DOMWrapperWorld> m_world;
     v8::Isolate* m_isolate;
 };
 
 }
 
 #endif // V8MutationCallback_h