Moves mash/wm into ash/mus

mash/wm/shelf_layout_manager_delegate.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 MASH_WM_SHELF_LAYOUT_MANAGER_DELEGATE_H_
-#define MASH_WM_SHELF_LAYOUT_MANAGER_DELEGATE_H_
-
-namespace mash {
-namespace wm {
-
-class ShelfLayoutManagerDelegate {
- public:
-  // Called when the window associated with the shelf is available. That is,
-  // ShelfLayoutManager::GetShelfWindow() returns non-null.
-  virtual void OnShelfWindowAvailable() = 0;
-
- protected:
-  virtual ~ShelfLayoutManagerDelegate() {}
-};
-
-}  // namespace wm
-}  // namespace mash
-
-#endif  // MASH_WM_SHELF_LAYOUT_MANAGER_DELEGATE_H_