Only create chromeHidden object when needed.

chrome/renderer/extensions/chrome_v8_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 CHROME_RENDERER_EXTENSIONS_CHROME_V8_EXTENSION_H_
 #define CHROME_RENDERER_EXTENSIONS_CHROME_V8_EXTENSION_H_
 #pragma once
 
 #include "base/logging.h"
 #include "base/memory/linked_ptr.h"
 #include "chrome/renderer/extensions/chrome_v8_extension_handler.h"
 #include "v8/include/v8.h"
 
 #include <map>
 #include <set>
 #include <string>
 
 class ChromeV8Context;
 class Extension;
 class ExtensionDispatcher;
 
 namespace content {
 class RenderView;
 }
 
 // This is a base class for chrome extension bindings.  Common features that
 // are shared by different modules go here.
-//
-// TODO(aa): Remove the extension-system specific bits of this and move to
-// renderer/, or even to renderer/bindings and use DEPS to enforce separation
-// from extension system.
-//
-// TODO(aa): Add unit testing for this class.
 class ChromeV8Extension : public v8::Extension {
  public:
   typedef std::set<ChromeV8Extension*> InstanceSet;
   static const InstanceSet& GetAll();
 
   ChromeV8Extension(const char* name,
                     int resource_id,
                     ExtensionDispatcher* extension_dispatcher);
   ChromeV8Extension(const char* name,
                     int resource_id,
                     int dependency_count,
                     const char** dependencies,
                     ExtensionDispatcher* extension_dispatcher);
   virtual ~ChromeV8Extension();
 
   ExtensionDispatcher* extension_dispatcher() { return extension_dispatcher_; }
 
-  // Returns a hidden variable for use by the bindings in the specified context
-  // that is unreachable by the page for the current context.
-  static v8::Handle<v8::Value> GetChromeHidden(
-      const v8::Handle<v8::Context>& context);
-
   void ContextWillBeReleased(ChromeV8Context* context);
 
   // Derived classes should call this at the end of their implementation in
   // order to expose common native functions, like GetChromeHidden, to the
   // v8 extension.
   virtual v8::Handle<v8::FunctionTemplate>
       GetNativeFunction(v8::Handle<v8::String> name) OVERRIDE;
 
  protected:
   template<class T>
@@ skipping 40 matching lines @@
 
   // Map of all current handlers.
   typedef std::map<ChromeV8Context*,
                    linked_ptr<ChromeV8ExtensionHandler> > HandlerMap;
   HandlerMap handlers_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeV8Extension);
 };
 
 #endif  // CHROME_RENDERER_EXTENSIONS_CHROME_V8_EXTENSION_H_