Refactors DockedWindowLayoutManager in terms of ash/wm/common

ash/wm/common/shelf/wm_shelf_constants.h

Index: ash/wm/common/shelf/wm_shelf_constants.h
diff --git a/ash/wm/common/shelf/wm_shelf_constants.h b/ash/wm/common/shelf/wm_shelf_constants.h
new file mode 100644
index 0000000000000000000000000000000000000000..e112d0aed20465b970046e6331b8003b28aba738
--- /dev/null
+++ b/ash/wm/common/shelf/wm_shelf_constants.h
@@ -0,0 +1,22 @@
+// 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_WM_COMMON_SHELF_WM_SHELF_CONSTANTS_H_
+#define ASH_WM_COMMON_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_WM_COMMON_SHELF_WM_SHELF_CONSTANTS_H_