Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/extensions/component_loader.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_EXTENSIONS_COMPONENT_LOADER_H_
 #define CHROME_BROWSER_EXTENSIONS_COMPONENT_LOADER_H_
 
 #include <string>
 #include <vector>
 
 #include "base/file_path.h"
 #include "base/gtest_prod_util.h"
 #include "base/prefs/public/pref_change_registrar.h"
+#include "base/prefs/public/pref_observer.h"
 #include "base/values.h"
-#include "content/public/browser/notification_observer.h"
 
 class ExtensionServiceInterface;
 class PrefService;
 
 namespace extensions {
 
 class Extension;
 
 // For registering, loading, and unloading component extensions.
-class ComponentLoader : public content::NotificationObserver {
+class ComponentLoader : public PrefObserver {
  public:
   ComponentLoader(ExtensionServiceInterface* extension_service,
                   PrefService* prefs,
                   PrefService* local_state);
   virtual ~ComponentLoader();
 
   size_t registered_extensions_count() const {
     return component_extensions_.size();
   }
 
@@ skipping 26 matching lines @@
   bool Exists(const std::string& id) const;
 
   // Unloads a component extension and removes it from the list of component
   // extensions to be loaded.
   void Remove(const FilePath& root_directory);
   void Remove(const std::string& id);
 
   // Adds the default component extensions.
   void AddDefaultComponentExtensions();
 
-  // 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;
 
   static void RegisterUserPrefs(PrefService* prefs);
 
   // Parse the given JSON manifest. Returns NULL if it cannot be parsed, or if
   // if the result is not a DictionaryValue.
   DictionaryValue* ParseManifest(const std::string& manifest_contents) const;
 
   // Clear the list of registered extensions.
   void ClearAllRegistered();
 
@@ skipping 52 matching lines @@
   PrefChangeRegistrar pref_change_registrar_;
 
   std::string script_bubble_id_;
 
   DISALLOW_COPY_AND_ASSIGN(ComponentLoader);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_COMPONENT_LOADER_H_