Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/ui/webui/ntp/app_launcher_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_NTP_APP_LAUNCHER_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_NTP_APP_LAUNCHER_HANDLER_H_
 
 #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/common/cancelable_request.h"
 #include "chrome/browser/extensions/extension_install_prompt.h"
 #include "chrome/browser/extensions/extension_uninstall_dialog.h"
 #include "chrome/browser/favicon/favicon_service.h"
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/extensions/extension_constants.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/web_ui_message_handler.h"
 #include "sync/api/string_ordinal.h"
 
 class ExtensionService;
 class PrefChangeRegistrar;
 class Profile;
 
 namespace extensions {
 class AppNotification;
 }
 
 // The handler for Javascript messages related to the "apps" view.
 class AppLauncherHandler : public content::WebUIMessageHandler,
                            public ExtensionUninstallDialog::Delegate,
                            public ExtensionInstallPrompt::Delegate,
-                           public content::NotificationObserver {
+                           public content::NotificationObserver,
+                           public PrefObserver {
  public:
   explicit AppLauncherHandler(ExtensionService* extension_service);
   virtual ~AppLauncherHandler();
 
   // Populate a dictionary with the information from an extension.
   static void CreateAppInfo(
       const extensions::Extension* extension,
       const extensions::AppNotification* notification,
       ExtensionService* service,
       base::DictionaryValue* value);
 
   // WebUIMessageHandler implementation.
   virtual void RegisterMessages() OVERRIDE;
 
   // content::NotificationObserver
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
+  // PrefObserver
+  virtual void OnPreferenceChanged(PrefServiceBase* service,
+                                   const std::string& pref_name) OVERRIDE;
+
   // Populate the given dictionary with all installed app info.
   void FillAppDictionary(base::DictionaryValue* value);
 
   // Create a dictionary value for the given extension. May return NULL, e.g. if
   // the given extension is not an app. If non-NULL, the caller assumes
   // ownership of the pointer.
   base::DictionaryValue* GetAppInfo(const extensions::Extension* extension);
 
   // Populate the given dictionary with the web store promo content.
   void FillPromoDictionary(base::DictionaryValue* value);
@@ skipping 134 matching lines @@
   // when the app is added to the page (via getAppsCallback or appAdded).
   std::string highlight_app_id_;
 
   // Hold state for favicon requests.
   CancelableRequestConsumerTSimple<AppInstallInfo*> favicon_consumer_;
 
   DISALLOW_COPY_AND_ASSIGN(AppLauncherHandler);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_NTP_APP_LAUNCHER_HANDLER_H_