Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/extensions/component_loader.cc

 // 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.
 
 #include "chrome/browser/extensions/component_loader.h"
 
 #include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/json/json_string_value_serializer.h"
 #include "base/path_service.h"
@@ skipping 389 matching lines @@
   // the browser process has started.
   AddOrReloadEnterpriseWebStore();
 
 #if defined(USE_ASH)
   AddChromeApp();
 #endif
 
   AddScriptBubble();
 }
 
-void ComponentLoader::Observe(
-    int type,
-    const content::NotificationSource& source,
-    const content::NotificationDetails& details) {
-  DCHECK_EQ(chrome::NOTIFICATION_PREF_CHANGED, type);
-  DCHECK_EQ(std::string(prefs::kEnterpriseWebStoreURL),
-            *content::Details<const std::string>(details).ptr());
+void ComponentLoader::OnPreferenceChanged(PrefServiceBase* service,
+                                          const std::string& pref_name) {
+  DCHECK_EQ(std::string(prefs::kEnterpriseWebStoreURL), pref_name);
   AddOrReloadEnterpriseWebStore();
 }
 
 // static
 void ComponentLoader::RegisterUserPrefs(PrefService* prefs) {
   prefs->RegisterStringPref(prefs::kEnterpriseWebStoreURL,
                             std::string() /* default_value */,
                             PrefService::UNSYNCABLE_PREF);
   prefs->RegisterStringPref(prefs::kEnterpriseWebStoreName,
                             std::string() /* default_value */,
                             PrefService::UNSYNCABLE_PREF);
 }
 
 }  // namespace extensions