[ash-md] Remove the number of animators used for the Shelf animations.

ash/common/shelf/wm_shelf.h

 // Copyright 2016 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_WM_SHELF_H_
 #define ASH_COMMON_SHELF_WM_SHELF_H_
 
 #include <memory>
 
 #include "ash/ash_export.h"
 #include "ash/common/shelf/shelf_layout_manager_observer.h"
 #include "ash/public/cpp/shelf_types.h"
 #include "base/observer_list.h"
 
 namespace gfx {
 class Rect;
 }
 
 namespace ui {
 class GestureEvent;
 }
 
 namespace ash {
 
+enum class AnimationChangeType;
 class ShelfBezelEventHandler;
 class ShelfLayoutManager;
 class ShelfLayoutManagerTest;
 class ShelfLockingManager;
 class ShelfView;
 class ShelfWidget;
 class StatusAreaWidget;
 class WmShelfObserver;
 class WmWindow;
 
@@ skipping 104 matching lines @@
   void SetVirtualKeyboardBoundsForTesting(const gfx::Rect& bounds);
   ShelfLockingManager* GetShelfLockingManagerForTesting();
   ShelfView* GetShelfViewForTesting();
 
  protected:
   // ShelfLayoutManagerObserver:
   void WillDeleteShelfLayoutManager() override;
   void WillChangeVisibilityState(ShelfVisibilityState new_state) override;
   void OnAutoHideStateChanged(ShelfAutoHideState new_state) override;
   void OnBackgroundUpdated(ShelfBackgroundType background_type,
-                           BackgroundAnimatorChangeType change_type) override;
+                           AnimationChangeType change_type) override;
 
  private:
   class AutoHideEventHandler;
   friend class ShelfLayoutManagerTest;
 
   // Layout manager for the shelf container window. Instances are constructed by
   // ShelfWidget and lifetimes are managed by the container windows themselves.
   ShelfLayoutManager* shelf_layout_manager_ = nullptr;
 
   std::unique_ptr<ShelfWidget> shelf_widget_;
@@ skipping 18 matching lines @@
   // Forwards touch gestures on a bezel sensor to the shelf.
   // TODO(mash): Facilitate simliar functionality in mash: crbug.com/636647
   std::unique_ptr<ShelfBezelEventHandler> bezel_event_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(WmShelf);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SHELF_WM_SHELF_H_