Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/extensions/api/managed_mode/managed_mode_api.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.
 
 // Defines the Chrome Extensions Managed Mode API relevant classes to realize
 // the API as specified in the extension API JSON.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_API_MANAGED_MODE_MANAGED_MODE_API_H_
 #define CHROME_BROWSER_EXTENSIONS_API_MANAGED_MODE_MANAGED_MODE_API_H_
 
 #include "base/prefs/public/pref_change_registrar.h"
+#include "base/prefs/public/pref_observer.h"
 #include "chrome/browser/extensions/extension_function.h"
 #include "content/public/browser/notification_observer.h"
 
 class Profile;
 
 namespace extensions {
 
-class ExtensionManagedModeEventRouter : public content::NotificationObserver {
+class ExtensionManagedModeEventRouter : public PrefObserver {
  public:
   explicit ExtensionManagedModeEventRouter(Profile* profile);
   virtual ~ExtensionManagedModeEventRouter();
 
   void Init();
 
-  // 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;
 
  private:
   PrefChangeRegistrar registrar_;
   Profile* profile_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionManagedModeEventRouter);
 };
 
 class GetManagedModeFunction : public SyncExtensionFunction {
  public:
@@ skipping 40 matching lines @@
  protected:
   virtual ~SetPolicyFunction();
 
   // ExtensionFunction:
   virtual bool RunImpl() OVERRIDE;
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_MANAGED_MODE_MANAGED_MODE_API_H_