Removed unneeded includes.

extensions/browser/app_sorting.h

 // Copyright (c) 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 EXTENSIONS_BROWSER_APP_SORTING_H_
 #define EXTENSIONS_BROWSER_APP_SORTING_H_
 
 #include <string>
 
 #include "base/basictypes.h"
-#include "extensions/browser/extension_prefs.h"
 #include "extensions/common/extension.h"
 #include "sync/api/string_ordinal.h"
 
 class ExtensionSyncService;
 
 namespace extensions {
 
 class ExtensionScopedPrefs;
 
 // An interface that provides a fixed ordering for a set of apps.
@@ skipping 91 matching lines @@
   // Hidden extensions don't appear in the new tab page.
   virtual void MarkExtensionAsHidden(const std::string& extension_id) = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(AppSorting);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_APP_SORTING_H_