Cheaper thread-safe atomic initialization of static references.

Source/core/dom/DOMArrayBuffer.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef DOMArrayBuffer_h
 #define DOMArrayBuffer_h
 
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "core/dom/DOMArrayBufferDeallocationObserver.h"
 #include "wtf/ArrayBuffer.h"
@@ skipping 37 matching lines @@
     PassRefPtr<DOMArrayBuffer> slice(int begin, int end) const
     {
         return create(buffer()->slice(begin, end));
     }
     PassRefPtr<DOMArrayBuffer> slice(int begin) const
     {
         return create(buffer()->slice(begin));
     }
     bool transfer(WTF::ArrayBufferContents& result) { return buffer()->transfer(result); }
     bool isNeutered() { return buffer()->isNeutered(); }
-    void setDeallocationObserver(DOMArrayBufferDeallocationObserver* observer)
+    void setDeallocationObserver(DOMArrayBufferDeallocationObserver& observer)
     {
         buffer()->setDeallocationObserver(observer);
     }
 
     virtual v8::Handle<v8::Object> wrap(v8::Handle<v8::Object> creationContext, v8::Isolate*) override;
     virtual v8::Handle<v8::Object> associateWithWrapper(v8::Isolate*, const WrapperTypeInfo*, v8::Handle<v8::Object> wrapper) override;
 
 private:
     explicit DOMArrayBuffer(PassRefPtr<WTF::ArrayBuffer> buffer)
         : m_buffer(buffer)
     {
         ASSERT(m_buffer);
     }
 
     RefPtr<WTF::ArrayBuffer> m_buffer;
 };
 
 } // namespace blink
 
 #endif // DOMArrayBuffer_h