Cleanup: Remove some unneeded Extension* class forward declarations.

chrome/browser/ui/app_list/search/app_search_provider.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_UI_APP_LIST_SEARCH_APP_SEARCH_PROVIDER_H_
 #define CHROME_BROWSER_UI_APP_LIST_SEARCH_APP_SEARCH_PROVIDER_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_vector.h"
 #include "chrome/browser/ui/app_list/search/search_provider.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 
 class AppListControllerDelegate;
-class ExtensionService;
 class Profile;
 
 namespace extensions {
 class ExtensionSet;
 }
 
 namespace app_list {
 
 class AppSearchProvider : public SearchProvider,
                           public content::NotificationObserver {
@@ skipping 24 matching lines @@
   content::NotificationRegistrar registrar_;
 
   Apps apps_;
 
   DISALLOW_COPY_AND_ASSIGN(AppSearchProvider);
 };
 
 }  // namespace app_list
 
 #endif  // CHROME_BROWSER_UI_APP_LIST_SEARCH_APP_SEARCH_PROVIDER_H_