Removes some dead code and includes

ash/mus/bridge/mus_layout_manager_adapter.cc

-// 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.
-
-#include "ash/mus/bridge/mus_layout_manager_adapter.h"
-
-#include "ash/common/wm_layout_manager.h"
-#include "ash/mus/bridge/wm_window_mus.h"
-#include "services/ui/public/cpp/window.h"
-
-namespace ash {
-namespace mus {
-
-MusLayoutManagerAdapter::MusLayoutManagerAdapter(
-    ui::Window* window,
-    std::unique_ptr<WmLayoutManager> layout_manager)
-    : window_(window),
-      layout_manager_(std::move(layout_manager)) {
-  window_->AddObserver(this);
-}
-
-MusLayoutManagerAdapter::~MusLayoutManagerAdapter() {
-  window_->RemoveObserver(this);
-}
-
-void MusLayoutManagerAdapter::OnTreeChanging(const TreeChangeParams& params) {
-  if (params.old_parent == window_) {
-    layout_manager_->OnWillRemoveWindowFromLayout(
-        WmWindowMus::Get(params.target));
-  }
-}
-
-void MusLayoutManagerAdapter::OnTreeChanged(const TreeChangeParams& params) {
-  if (params.new_parent == window_)
-    layout_manager_->OnWindowAddedToLayout(WmWindowMus::Get(params.target));
-  else if (params.old_parent == window_)
-    layout_manager_->OnWindowRemovedFromLayout(WmWindowMus::Get(params.target));
-}
-
-void MusLayoutManagerAdapter::OnWindowBoundsChanged(
-    ui::Window* window,
-    const gfx::Rect& old_bounds,
-    const gfx::Rect& new_bounds) {
-  layout_manager_->OnWindowResized();
-}
-
-void MusLayoutManagerAdapter::OnChildWindowVisibilityChanged(ui::Window* window,
-                                                             bool visible) {
-  layout_manager_->OnChildWindowVisibilityChanged(WmWindowMus::Get(window),
-                                                  visible);
-}
-
-}  // namespace mus
-}  // namespace ash