Remove ArrayBufferDeallocationObserver

Source/core/dom/DOMArrayBuffer.cpp

Index: Source/core/dom/DOMArrayBuffer.cpp
diff --git a/Source/core/dom/DOMArrayBuffer.cpp b/Source/core/dom/DOMArrayBuffer.cpp
index 41fdae243981748fd6fc8390497f5bd824fe493a..7556aec914f04a59e53453e910a26083e69f2a87 100644
--- a/Source/core/dom/DOMArrayBuffer.cpp
+++ b/Source/core/dom/DOMArrayBuffer.cpp
@@ -7,7 +7,6 @@
 
 #include "bindings/core/v8/DOMDataStore.h"
 #include "bindings/core/v8/V8DOMWrapper.h"
-#include "core/dom/DOMArrayBufferDeallocationObserver.h"
 
 namespace blink {
 
@@ -23,12 +22,6 @@ v8::Local<v8::Object> DOMArrayBuffer::wrap(v8::Isolate* isolate, v8::Local<v8::O
     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);
 }