Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/profiles/off_the_record_profile_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_PROFILES_OFF_THE_RECORD_PROFILE_IMPL_H_
 #define CHROME_BROWSER_PROFILES_OFF_THE_RECORD_PROFILE_IMPL_H_
 
 #include <string>
 
 #include "base/gtest_prod_util.h"
 #include "chrome/browser/profiles/off_the_record_profile_io_data.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser_list.h"
 #include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
 
 using base::Time;
 using base::TimeDelta;
 
 ////////////////////////////////////////////////////////////////////////////////
 //
 // OffTheRecordProfileImpl is a profile subclass that wraps an existing profile
 // to make it suitable for the incognito mode.
 //
 // Note: This class is a leaf class and is not intended for subclassing.
@@ skipping 111 matching lines @@
   Time start_time_;
 
   FilePath last_selected_directory_;
 
   scoped_ptr<PrefProxyConfigTracker> pref_proxy_config_tracker_;
 
   DISALLOW_COPY_AND_ASSIGN(OffTheRecordProfileImpl);
 };
 
 #endif  // CHROME_BROWSER_PROFILES_OFF_THE_RECORD_PROFILE_IMPL_H_