mash: Migrate ShelfButton* to wm common types

ash/shelf/shelf.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_SHELF_SHELF_H_
 #define ASH_SHELF_SHELF_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 138 matching lines @@
   // system.
   gfx::Rect GetVisibleItemsBoundsInScreen() const;
 
   // Returns ApplicationDragAndDropHost for this shelf.
   app_list::ApplicationDragAndDropHost* GetDragAndDropHostForAppList();
 
   ShelfLockingManager* shelf_locking_manager_for_testing() {
     return &shelf_locking_manager_;
   }
 
+  ShelfView* shelf_view_for_testing() { return shelf_view_; }
+
  private:
   friend class test::ShelfTestAPI;
 
   // The shelf controller. Owned by the root window controller.
   WmShelf* wm_shelf_;
   ShelfWidget* shelf_widget_;
   ShelfView* shelf_view_;
   ShelfLockingManager shelf_locking_manager_;
 
   ShelfAlignment alignment_ = SHELF_ALIGNMENT_BOTTOM;
   ShelfAutoHideBehavior auto_hide_behavior_ = SHELF_AUTO_HIDE_BEHAVIOR_NEVER;
 
   DISALLOW_COPY_AND_ASSIGN(Shelf);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SHELF_SHELF_H_