Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/notifications/notification_ui_manager_impl.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_NOTIFICATIONS_NOTIFICATION_UI_MANAGER_IMPL_H_
 #define CHROME_BROWSER_NOTIFICATIONS_NOTIFICATION_UI_MANAGER_IMPL_H_
 
 #include <deque>
 #include <string>
 #include <vector>
 
 #include "base/id_map.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/prefs/public/pref_observer.h"
 #include "base/timer.h"
 #include "chrome/browser/api/prefs/pref_member.h"
 #include "chrome/browser/notifications/balloon.h"
 #include "chrome/browser/notifications/balloon_collection.h"
 #include "chrome/browser/notifications/notification_prefs_manager.h"
 #include "chrome/browser/notifications/notification_ui_manager.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 
 class Notification;
 class PrefService;
 class Profile;
 class QueuedNotification;
 
 // The notification manager manages use of the desktop for notifications.
 // It maintains a queue of pending notifications when space becomes constrained.
 class NotificationUIManagerImpl
     : public NotificationUIManager,
       public NotificationPrefsManager,
       public BalloonCollection::BalloonSpaceChangeListener,
-      public content::NotificationObserver {
+      public content::NotificationObserver,
+      public PrefObserver {
  public:
   explicit NotificationUIManagerImpl(PrefService* local_state);
   virtual ~NotificationUIManagerImpl();
 
   // Initializes the UI manager with a balloon collection; this object
   // takes ownership of the balloon collection.
   void Initialize(BalloonCollection* balloon_collection);
 
   // NotificationUIManager:
   virtual void Add(const Notification& notification,
@@ skipping 11 matching lines @@
       GetPositionPreference() const OVERRIDE;
   virtual void SetPositionPreference(
       BalloonCollection::PositionPreference preference) OVERRIDE;
 
  private:
   // content::NotificationObserver override.
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
+  // PrefObserver override.
+  virtual void OnPreferenceChanged(PrefServiceBase* service,
+                                   const std::string& pref_name) OVERRIDE;
+
   // Attempts to display notifications from the show_queue if the user
   // is active.
   void CheckAndShowNotifications();
 
   // Attempts to display notifications from the show_queue.
   void ShowNotifications();
 
   // BalloonCollectionObserver implementation.
   virtual void OnBalloonSpaceChanged() OVERRIDE;
 
@@ skipping 18 matching lines @@
   IntegerPrefMember position_pref_;
 
   // Used by screen-saver and full-screen handling support.
   bool is_user_active_;
   base::RepeatingTimer<NotificationUIManagerImpl> user_state_check_timer_;
 
   DISALLOW_COPY_AND_ASSIGN(NotificationUIManagerImpl);
 };
 
 #endif  // CHROME_BROWSER_NOTIFICATIONS_NOTIFICATION_UI_MANAGER_IMPL_H_