Remove content::NotificationObserver dependency from most Prefs code.

chrome/common/chrome_notification_types.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_COMMON_CHROME_NOTIFICATION_TYPES_H_
 #define CHROME_COMMON_CHROME_NOTIFICATION_TYPES_H_
 
 #include "build/build_config.h"
 #include "content/public/browser/notification_types.h"
 
@@ skipping 388 matching lines @@
   NOTIFICATION_TEMPLATE_URL_SERVICE_LOADED,
 
   // Sent when a TemplateURL is removed from the model. The source is the
   // Profile, and the details the id of the TemplateURL being removed.
   NOTIFICATION_TEMPLATE_URL_REMOVED,
 
   // Sent when the prefs relating to the default search engine have changed due
   // to policy.  Source and details are unused.
   NOTIFICATION_DEFAULT_SEARCH_POLICY_CHANGED,
 
-  // This is sent to a pref observer when a pref is changed. The source is the
-  // PrefService and the details a std::string of the changed path.
-  NOTIFICATION_PREF_CHANGED,
-
-  // This is broadcast after the preference subsystem has completed
-  // asynchronous initalization of a PrefService.
-  NOTIFICATION_PREF_INITIALIZATION_COMPLETED,
-
   // The state of a web resource has been changed. A resource may have been
   // added, removed, or altered. Source is WebResourceService, and the
   // details are NoDetails.
   NOTIFICATION_PROMO_RESOURCE_STATE_CHANGED,
 
   // A safe browsing database update completed.  Source is the
   // SafeBrowsingService and the details are a bool indicating whether the
   // update was successful.
   NOTIFICATION_SAFE_BROWSING_UPDATE_COMPLETE,
 
@@ skipping 851 matching lines @@
   // Currently only Content and Chrome define and use notifications.
   // Custom notifications not belonging to Content and Chrome should start
   // from here.
   NOTIFICATION_CHROME_END,
 };
 
 }  // namespace chrome
 
 
 #endif  // CHROME_COMMON_CHROME_NOTIFICATION_TYPES_H_