Remove ArrayBufferDeallocationObserver

Source/core/dom/DOMArrayBuffer.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/DOMArrayBuffer.h"
 
 #include "bindings/core/v8/DOMDataStore.h"
 #include "bindings/core/v8/V8DOMWrapper.h"
-#include "core/dom/DOMArrayBufferDeallocationObserver.h"
 
 namespace blink {
 
 v8::Local<v8::Object> DOMArrayBuffer::wrap(v8::Isolate* isolate, v8::Local<v8::Object> creationContext)
 {
     // It's possible that no one except for the new wrapper owns this object at
     // this moment, so we have to prevent GC to collect this object until the
     // object gets associated with the wrapper.
     RefPtr<DOMArrayBuffer> protect(this);
 
     ASSERT(!DOMDataStore::containsWrapper(this, isolate));
 
     const WrapperTypeInfo* wrapperTypeInfo = this->wrapperTypeInfo();
     v8::Local<v8::Object> wrapper = v8::ArrayBuffer::New(isolate, data(), byteLength());
 
-    // Only when we create a new wrapper, let V8 know that we allocated and
-    // associated a new memory block with the wrapper. Note that
-    // setDeallocationObserver implicitly calls
-    // DOMArrayBufferDeallocationObserver::blinkAllocatedMemory.
-    buffer()->setDeallocationObserver(DOMArrayBufferDeallocationObserver::instance());
-
     return associateWithWrapper(isolate, wrapperTypeInfo, wrapper);
 }
 
 v8::Local<v8::Object> DOMArrayBuffer::associateWithWrapper(v8::Isolate* isolate, const WrapperTypeInfo* wrapperTypeInfo, v8::Local<v8::Object> wrapper)
 {
     // This function does not set a deallocation observer to the underlying
     // array buffer.  It's a caller's duty.
 
     return V8DOMWrapper::associateObjectWithWrapper(isolate, this, wrapperTypeInfo, wrapper);
 }
 
 } // namespace blink