Drop more dependencies of ProfileKeyedService infrastructure on chrome.

chrome/browser/google_apis/drive_notification_manager_factory.h

 // Copyright 2013 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_GOOGLE_APIS_DRIVE_NOTIFICATION_MANAGER_FACTORY_H_
 #define CHROME_BROWSER_GOOGLE_APIS_DRIVE_NOTIFICATION_MANAGER_FACTORY_H_
 
 #include "base/memory/singleton.h"
 #include "chrome/browser/profiles/profile_keyed_service_factory.h"
 
+class Profile;
+
 namespace google_apis {
 
 class DriveNotificationManager;
 
 // Singleton that owns all DriveNotificationManager and associates them with
 // profiles.
 class DriveNotificationManagerFactory : public ProfileKeyedServiceFactory {
  public:
   static DriveNotificationManager* GetForProfile(Profile* profile);
 
   static DriveNotificationManagerFactory* GetInstance();
 
  private:
   friend struct DefaultSingletonTraits<DriveNotificationManagerFactory>;
 
   DriveNotificationManagerFactory();
   virtual ~DriveNotificationManagerFactory();
 
   // ProfileKeyedServiceFactory implementation.
   virtual ProfileKeyedService* BuildServiceInstanceFor(
       content::BrowserContext* profile) const OVERRIDE;
 };
 
 }  // namespace google_apis
 
 #endif  // CHROME_BROWSER_GOOGLE_APIS_DRIVE_NOTIFICATION_MANAGER_FACTORY_H_