Cleanup of v8 extension stuff. Playback extension is only used in chrome, so move it to chrome\rend…

webkit/extensions/v8/heap_profiler_extension.h

-// Copyright (c) 2011 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 WEBKIT_EXTENSIONS_V8_HEAP_PROFILER_EXTENSION_H_
-#define WEBKIT_EXTENSIONS_V8_HEAP_PROFILER_EXTENSION_H_
-#pragma once
-
-#include "webkit/extensions/webkit_extensions_export.h"
-
-namespace v8 {
-class Extension;
-}
-
-namespace extensions_v8 {
-
-// HeapProfilerExtension is a V8 extension to expose a JS function for
-// dumping native heap profiles. This should only be used for debugging.
-class HeapProfilerExtension {
- public:
-  WEBKIT_EXTENSIONS_EXPORT static v8::Extension* Get();
-};
-
-}  // namespace extensions_v8
-
-#endif  // WEBKIT_EXTENSIONS_V8_HEAP_PROFILER_EXTENSION_H_