ash: Cleanup class/struct forward declarations

ash/common/shelf/shelf_delegate.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 ASH_COMMON_SHELF_SHELF_DELEGATE_H_
 #define ASH_COMMON_SHELF_SHELF_DELEGATE_H_
 
 #include <string>
 
 #include "ash/ash_export.h"
 #include "ash/common/shelf/shelf_item_types.h"
 
 namespace ash {
 
-class WmShelf;
-
 // Delegate shared by all shelf instances.
 class ASH_EXPORT ShelfDelegate {
  public:
   virtual ~ShelfDelegate() {}
 
   // Get the shelf ID from an application ID.
   virtual ShelfID GetShelfIDForAppID(const std::string& app_id) = 0;
 
   // Get the shelf ID from an application ID and a launch ID.
   // The launch ID can be passed to an app when launched in order to support
@@ skipping 21 matching lines @@
   // Check if the app with |app_id_| is pinned to the shelf.
   virtual bool IsAppPinned(const std::string& app_id) = 0;
 
   // Unpins app item with |app_id|.
   virtual void UnpinAppWithID(const std::string& app_id) = 0;
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SHELF_SHELF_DELEGATE_H_