Reland of "Apply Shelf/Dock opacity animations for the Material Design style."

ash/shelf/shelf_view.h

 // Copyright (c) 2012 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_VIEW_H_
 #define ASH_SHELF_SHELF_VIEW_H_
 
 #include <memory>
 #include <string>
 #include <utility>
@@ skipping 141 matching lines @@
   void PointerPressedOnButton(views::View* view,
                               Pointer pointer,
                               const ui::LocatedEvent& event);
   void PointerDraggedOnButton(views::View* view,
                               Pointer pointer,
                               const ui::LocatedEvent& event);
   void PointerReleasedOnButton(views::View* view,
                                Pointer pointer,
                                bool canceled);
 
+  // Updates the background for the shelf items.
+  void UpdateShelfItemBackground(int alpha);
+
   // Return the view model for test purposes.
   const views::ViewModel* view_model_for_test() const {
     return view_model_.get();
   }
 
  private:
   friend class ash::test::ShelfViewTestAPI;
 
   class FadeOutAnimationDelegate;
   class StartFadeAnimationDelegate;
@@ skipping 295 matching lines @@
 
   // Tracks UMA metrics based on shelf button press actions.
   ShelfButtonPressedMetricTracker shelf_button_pressed_metric_tracker_;
 
   DISALLOW_COPY_AND_ASSIGN(ShelfView);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SHELF_SHELF_VIEW_H_