mash: Move ash/common/wm/shelf to ash/common/shelf

ash/common/wm/shelf/wm_shelf_constants.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_WM_SHELF_WM_SHELF_CONSTANTS_H_
-#define ASH_COMMON_WM_SHELF_WM_SHELF_CONSTANTS_H_
-
-#include "ash/ash_export.h"
-
-namespace ash {
-namespace wm {
-
-// Max alpha of the shelf background.
-ASH_EXPORT extern const int kShelfBackgroundAlpha;
-
-// Animation duration for switching black shelf and dock background on and off.
-ASH_EXPORT extern const int kTimeToSwitchBackgroundMs;
-
-}  // namespace wm
-}  // namespace ash
-
-#endif  // ASH_COMMON_WM_SHELF_WM_SHELF_CONSTANTS_H_