Only create chromeHidden object when needed.

chrome/renderer/extensions/chrome_v8_context.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_CONTEXT_H_
 #define CHROME_RENDERER_EXTENSIONS_CHROME_V8_CONTEXT_H_
 #pragma once
 
 #include <string>
 
@@ skipping 28 matching lines @@
     return extension_id_;
   }
 
   WebKit::WebFrame* web_frame() const {
     return web_frame_;
   }
   void clear_web_frame() {
     web_frame_ = NULL;
   }
 
+  // Returns a special Chrome-specific hidden object that is associated with a
+  // context, but not reachable from the JavaScript in that context. This is
+  // used by our v8::Extension implementations as a way to share code and as a
+  // bridge between C++ and JavaScript.
+  static v8::Handle<v8::Value> GetOrCreateChromeHidden(
+      v8::Handle<v8::Context> context);
+
+  // Return the chromeHidden object associated with this context, or an empty
+  // handle if no chrome hidden has been created (by GetOrCreateChromeHidden)
+  // yet for this context.
+  v8::Handle<v8::Value> GetChromeHidden() const;
+
   // Returns the RenderView associated with this context. Can return NULL if the
   // context is in the process of being destroyed.
   content::RenderView* GetRenderView() const;
 
   // Fires the onload and onunload events on the chromeHidden object.
   // TODO(aa): Move this to EventBindings.
   void DispatchOnLoadEvent(bool is_extension_process,
                            bool is_incognito_process) const;
   void DispatchOnUnloadEvent() const;
 
@@ skipping 21 matching lines @@
   // object can outlive is destroyed asynchronously.
   WebKit::WebFrame* web_frame_;
 
   // The extension ID this context is associated with.
   std::string extension_id_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeV8Context);
 };
 
 #endif  // CHROME_RENDERER_EXTENSIONS_CHROME_V8_CONTEXT_H_