Cheaper thread-safe atomic initialization of static references.

Source/core/dom/DOMArrayBufferDeallocationObserver.cpp

 // 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.
 
 #include "config.h"
 #include "core/dom/DOMArrayBufferDeallocationObserver.h"
 
 #include "wtf/Threading.h"
 #include <v8.h>
 
 namespace blink {
 
-DOMArrayBufferDeallocationObserver* DOMArrayBufferDeallocationObserver::instance()
+DOMArrayBufferDeallocationObserver& DOMArrayBufferDeallocationObserver::instance()
 {
-    AtomicallyInitializedStatic(
-        DOMArrayBufferDeallocationObserver*,
-        deallocationObserver = new DOMArrayBufferDeallocationObserver);
+    AtomicallyInitializedStaticReference(DOMArrayBufferDeallocationObserver, deallocationObserver, new DOMArrayBufferDeallocationObserver);
     return deallocationObserver;
 }
 
 void DOMArrayBufferDeallocationObserver::arrayBufferDeallocated(unsigned sizeInBytes)
 {
     v8::Isolate::GetCurrent()->AdjustAmountOfExternalAllocatedMemory(-static_cast<int>(sizeInBytes));
 }
 
 void DOMArrayBufferDeallocationObserver::blinkAllocatedMemory(unsigned sizeInBytes)
 {
     v8::Isolate::GetCurrent()->AdjustAmountOfExternalAllocatedMemory(static_cast<int>(sizeInBytes));
 }
 
 } // namespace blink