Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/ui/webui/options/content_settings_handler.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_WEBUI_OPTIONS_CONTENT_SETTINGS_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_OPTIONS_CONTENT_SETTINGS_HANDLER_H_
 
 #include <map>
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/prefs/public/pref_change_registrar.h"
+#include "base/prefs/public/pref_observer.h"
 #include "chrome/browser/pepper_flash_settings_manager.h"
 #include "chrome/browser/ui/webui/options/options_ui.h"
 #include "chrome/common/content_settings.h"
 #include "chrome/common/content_settings_types.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 
 class HostContentSettingsMap;
 class ProtocolHandlerRegistry;
 
 namespace options {
 
 class ContentSettingsHandler : public OptionsPageUIHandler,
-                               public PepperFlashSettingsManager::Client {
+                               public PepperFlashSettingsManager::Client,
+                               public PrefObserver {
  public:
   ContentSettingsHandler();
   virtual ~ContentSettingsHandler();
 
   // OptionsPageUIHandler implementation.
   virtual void GetLocalizedValues(
       base::DictionaryValue* localized_strings) OVERRIDE;
   virtual void InitializeHandler() OVERRIDE;
   virtual void InitializePage() OVERRIDE;
   virtual void RegisterMessages() OVERRIDE;
 
   // content::NotificationObserver implementation.
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
+  // PrefObserver implementation.
+  virtual void OnPreferenceChanged(PrefServiceBase* service,
+                                   const std::string& pref_name) OVERRIDE;
+
   // PepperFlashSettingsManager::Client implementation.
   virtual void OnGetPermissionSettingsCompleted(
       uint32 request_id,
       bool success,
       PP_Flash_BrowserOperations_Permission default_permission,
       const ppapi::FlashSiteSettings& sites) OVERRIDE;
 
   // Gets a string identifier for the group name, for use in HTML.
   static std::string ContentSettingsTypeToGroupName(ContentSettingsType type);
 
@@ skipping 130 matching lines @@
 
   static const ExContentSettingsTypeNameEntry
       kExContentSettingsTypeGroupNames[];
 
   DISALLOW_COPY_AND_ASSIGN(ContentSettingsHandler);
 };
 
 }  // namespace options
 
 #endif  // CHROME_BROWSER_UI_WEBUI_OPTIONS_CONTENT_SETTINGS_HANDLER_H_