Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/ui/webui/extensions/extension_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_EXTENSIONS_EXTENSION_SETTINGS_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_EXTENSIONS_EXTENSION_SETTINGS_HANDLER_H_
 
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/prefs/public/pref_change_registrar.h"
+#include "base/prefs/public/pref_observer.h"
 #include "chrome/browser/extensions/extension_install_ui.h"
 #include "chrome/browser/extensions/extension_uninstall_dialog.h"
 #include "chrome/browser/extensions/extension_warning_set.h"
 #include "chrome/browser/extensions/requirements_checker.h"
 #include "chrome/common/extensions/extension_resource.h"
 #include "content/public/browser/navigation_controller.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents_observer.h"
@@ skipping 28 matching lines @@
   GURL url;
   int render_process_id;
   int render_view_id;
   bool incognito;
 };
 
 // Extension Settings UI handler.
 class ExtensionSettingsHandler
     : public content::WebUIMessageHandler,
       public content::NotificationObserver,
+      public PrefObserver,
       public content::WebContentsObserver,
       public ui::SelectFileDialog::Listener,
       public ExtensionUninstallDialog::Delegate,
       public base::SupportsWeakPtr<ExtensionSettingsHandler>{
  public:
   ExtensionSettingsHandler();
   virtual ~ExtensionSettingsHandler();
 
   static void RegisterUserPrefs(PrefService* prefs);
 
@@ skipping 28 matching lines @@
                             int index, void* params) OVERRIDE;
   virtual void MultiFilesSelected(
       const std::vector<FilePath>& files, void* params) OVERRIDE;
   virtual void FileSelectionCanceled(void* params) 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;
+
   // ExtensionUninstallDialog::Delegate implementation, used for receiving
   // notification about uninstall confirmation dialog selections.
   virtual void ExtensionUninstallAccepted() OVERRIDE;
   virtual void ExtensionUninstallCanceled() OVERRIDE;
 
   // Helper method that reloads all unpacked extensions.
   void ReloadUnpackedExtensions();
 
   // Callback for "requestExtensionsData" message.
   void HandleRequestExtensionsData(const base::ListValue* args);
@@ skipping 107 matching lines @@
 
   // This will not be empty when a requirements check is in progress. Doing
   // another Check() before the previous one is complete will cause the first
   // one to abort.
   scoped_ptr<extensions::RequirementsChecker> requirements_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionSettingsHandler);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_EXTENSIONS_EXTENSION_SETTINGS_HANDLER_H_