Show "Update Chrome OS" in the wrench menu, when the update image is ready.

chrome/browser/dom_ui/options/about_page_handler.h

 // Copyright (c) 2010 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_BROWSER_DOM_UI_OPTIONS_ABOUT_PAGE_HANDLER_H_
 #define CHROME_BROWSER_DOM_UI_OPTIONS_ABOUT_PAGE_HANDLER_H_
 
 #include <string>
 
 #include "chrome/browser/dom_ui/options/options_ui.h"
@@ skipping 11 matching lines @@
 
   // OptionsUIHandler implementation.
   virtual void GetLocalizedValues(DictionaryValue* localized_strings);
   virtual void RegisterMessages();
 
  private:
 
   void PageReady(const ListValue* args);
 
 #if defined(OS_CHROMEOS)
+  // Initiates update check.
   void CheckNow(const ListValue* args);
+
+  // Restarts the system.
+  void RestartNow(const ListValue* args);
+
   // Callback from chromeos::VersionLoader giving the version.
   void OnOSVersion(chromeos::VersionLoader::Handle handle,
                    std::string version);
   void UpdateStatus(const chromeos::UpdateLibrary::Status& status);
 
   // Handles asynchronously loading the version.
   chromeos::VersionLoader loader_;
 
   // Used to request the version.
   CancelableRequestConsumer consumer_;
 
   // Update Observer
   class UpdateObserver;
   scoped_ptr<UpdateObserver> update_observer_;
 
   int progress_;
   bool sticky_;
   bool started_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(AboutPageHandler);
 };
 
 #endif  // CHROME_BROWSER_DOM_UI_OPTIONS_ABOUT_PAGE_HANDLER_H_