Remove Ash shelf dimmer.

ash/common/shelf/wm_dimmer_view.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_DIMMER_VIEW_H_
-#define ASH_COMMON_SHELF_WM_DIMMER_VIEW_H_
-
-namespace views {
-class Widget;
-}
-
-namespace ash {
-
-// An interface around a widget and view that dim shelf items slightly when a
-// window is maximized and visible. See DimmerView for details. This interface
-// exists to avoid dependencies between ash common shelf code and the aura-only
-// implementation of DimmerView.
-// TODO(jamescook): Delete this after material design ships, as MD will not
-// require shelf dimming. http://crbug.com/614453
-class WmDimmerView {
- public:
-  // Returns the widget that holds the dimmer view.
-  virtual views::Widget* GetDimmerWidget() = 0;
-
-  // Force the dimmer to be undimmed (e.g. by an open context menu).
-  virtual void ForceUndimming(bool force) = 0;
-
-  // Returns the current alpha used by the dimming bar.
-  virtual int GetDimmingAlphaForTest() = 0;
-
- protected:
-  virtual ~WmDimmerView() {}
-};
-
-}  // namespace ash
-
-#endif  // ASH_COMMON_SHELF_WM_DIMMER_VIEW_H_