Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/extensions/api/managed_mode/managed_mode_api.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.
 
 // Implementation of the Chrome Extensions Managed Mode API.
 
 #include "chrome/browser/extensions/api/managed_mode/managed_mode_api.h"
 
 #include <string>
 
@@ skipping 32 matching lines @@
 }
 
 void ExtensionManagedModeEventRouter::Init() {
   registrar_.Init(g_browser_process->local_state());
   registrar_.Add(prefs::kInManagedMode, this);
 }
 
 ExtensionManagedModeEventRouter::~ExtensionManagedModeEventRouter() {
 }
 
-void ExtensionManagedModeEventRouter::Observe(
-    int type,
-    const content::NotificationSource& source,
-    const content::NotificationDetails& details) {
-  DCHECK_EQ(chrome::NOTIFICATION_PREF_CHANGED, type);
-  const std::string& pref_name =
-      *content::Details<std::string>(details).ptr();
+void ExtensionManagedModeEventRouter::OnPreferenceChanged(
+    PrefServiceBase* service,
+    const std::string& pref_name) {
   DCHECK_EQ(std::string(prefs::kInManagedMode), pref_name);
 
   DictionaryValue* dict = new DictionaryValue();
   dict->SetBoolean(
       keys::kValue,
       g_browser_process->local_state()->GetBoolean(prefs::kInManagedMode));
   scoped_ptr<ListValue> args(new ListValue());
   args->Set(0, dict);
 
   extensions::EventRouter* event_router = profile_->GetExtensionEventRouter();
@@ skipping 53 matching lines @@
   EXTENSION_FUNCTION_VALIDATE(args_->Get(1, &value));
 #if defined(ENABLE_CONFIGURATION_POLICY)
   policy::ManagedModePolicyProvider* policy_provider =
       profile_->GetManagedModePolicyProvider();
   policy_provider->SetPolicy(key, value);
 #endif
   return true;
 }
 
 }  // namespace extensions