Removes some dead code and includes

ash/mus/bridge/mus_layout_manager_adapter.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_MUS_BRIDGE_MUS_LAYOUT_MANAGER_ADAPTER_H_
-#define ASH_MUS_BRIDGE_MUS_LAYOUT_MANAGER_ADAPTER_H_
-
-#include <memory>
-
-#include "base/macros.h"
-#include "services/ui/public/cpp/window_observer.h"
-
-namespace ash {
-class WmLayoutManager;
-
-namespace mus {
-
-// Used to associate a ui::Window with an WmLayoutManager. This
-// attaches an observer to the ui::Window and calls the appropriate methods on
-// the WmLayoutManager at the appropriate time.
-//
-// NOTE: WmLayoutManager provides the function SetChildBounds(). This is
-// expected to be called to change the bounds of the Window. For aura this
-// function is called by way of aura exposing a hook (aura::LayoutManager). Mus
-// has no such hook. To ensure SetChildBounds() is called correctly all bounds
-// changes to ui::Windows must be routed through WmWindowMus. WmWindowMus
-// ensures WmLayoutManager::SetChildBounds() is called appropriately.
-class MusLayoutManagerAdapter : public ui::WindowObserver {
- public:
-  MusLayoutManagerAdapter(ui::Window* window,
-                          std::unique_ptr<WmLayoutManager> layout_manager);
-  ~MusLayoutManagerAdapter() override;
-
-  WmLayoutManager* layout_manager() { return layout_manager_.get(); }
-
- private:
-  // ui::WindowObserver:
-  void OnTreeChanging(const TreeChangeParams& params) override;
-  void OnTreeChanged(const TreeChangeParams& params) override;
-  void OnWindowBoundsChanged(ui::Window* window,
-                             const gfx::Rect& old_bounds,
-                             const gfx::Rect& new_bounds) override;
-  void OnChildWindowVisibilityChanged(ui::Window* window,
-                                      bool visible) override;
-
-  ui::Window* window_;
-  std::unique_ptr<WmLayoutManager> layout_manager_;
-
-  DISALLOW_COPY_AND_ASSIGN(MusLayoutManagerAdapter);
-};
-
-}  // namespace mus
-}  // namespace ash
-
-#endif  // ASH_MUS_BRIDGE_MUS_LAYOUT_MANAGER_ADAPTER_H_