Revert of Revert of Elimate NOTIFICATION_GOOGLE_URL_UPDATED

chrome/browser/ui/navigation_correction_tab_observer.h

 // Copyright (c) 2012 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_UI_NAVIGATION_CORRECTION_TAB_OBSERVER_H_
 #define CHROME_BROWSER_UI_NAVIGATION_CORRECTION_TAB_OBSERVER_H_
 
 #include "base/prefs/pref_change_registrar.h"
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
+#include "chrome/browser/google/google_url_tracker.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
 
 class Profile;
 
 namespace user_prefs {
 class PrefRegistrySyncable;
 }
 
 // Per-tab class to implement navigation suggestion service functionality.
 class NavigationCorrectionTabObserver
     : public content::WebContentsObserver,
-      public content::NotificationObserver,
       public content::WebContentsUserData<NavigationCorrectionTabObserver> {
  public:
   virtual ~NavigationCorrectionTabObserver();
 
   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
 
  private:
   explicit NavigationCorrectionTabObserver(content::WebContents* web_contents);
   friend class content::WebContentsUserData<NavigationCorrectionTabObserver>;
 
   // content::WebContentsObserver overrides:
   virtual void RenderViewCreated(
       content::RenderViewHost* render_view_host) OVERRIDE;
 
-  // content::NotificationObserver overrides:
-  virtual void Observe(int type,
-                       const content::NotificationSource& source,
-                       const content::NotificationDetails& details) OVERRIDE;
+  // Internal helpers ----------------------------------------------------------
 
-  // Internal helpers ----------------------------------------------------------
+  // Callback that is called when the Google URL is updated.
+  void OnGoogleURLUpdated(GURL old_url, GURL new_url);
 
   // Returns the URL for the correction service.  If the returned URL
   // is empty, the default error pages will be used.
   GURL GetNavigationCorrectionURL() const;
 
   // Called when navigation corrections are enabled or disabled.
   void OnEnabledChanged();
 
   // Updates the renderer's navigation correction service configuration.
   void UpdateNavigationCorrectionInfo(content::RenderViewHost* rvh);
 
   Profile* profile_;
-  content::NotificationRegistrar registrar_;
   PrefChangeRegistrar pref_change_registrar_;
+  scoped_ptr<GoogleURLTracker::Subscription> google_url_updated_subscription_;
 
   DISALLOW_COPY_AND_ASSIGN(NavigationCorrectionTabObserver);
 };
 
 #endif  // CHROME_BROWSER_UI_NAVIGATION_CORRECTION_TAB_OBSERVER_H_