Splits ToplevelWindowEventHandler into two

mash/wm/bridge/wm_window_mus.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_BRIDGE_WM_WINDOW_MUS_H_
 #define MASH_WM_BRIDGE_WM_WINDOW_MUS_H_
 
 #include <memory>
 
 #include "ash/wm/common/wm_window.h"
@@ skipping 144 matching lines @@
   bool CanMinimize() const override;
   bool CanResize() const override;
   bool CanActivate() const override;
   void StackChildAtTop(ash::wm::WmWindow* child) override;
   void StackChildAtBottom(ash::wm::WmWindow* child) override;
   void StackChildAbove(ash::wm::WmWindow* child,
                        ash::wm::WmWindow* target) override;
   void StackChildBelow(ash::wm::WmWindow* child,
                        ash::wm::WmWindow* target) override;
   std::vector<ash::wm::WmWindow*> GetChildren() override;
+  void ShowResizeShadow(int component) override;
+  void HideResizeShadow() override;
   void SnapToPixelBoundaryIfNecessary() override;
   void AddObserver(ash::wm::WmWindowObserver* observer) override;
   void RemoveObserver(ash::wm::WmWindowObserver* observer) override;
 
  private:
   // mus::WindowObserver:
   void OnTreeChanged(const TreeChangeParams& params) override;
   void OnWindowReordered(mus::Window* window,
                          mus::Window* relative_window,
                          mus::mojom::OrderDirection direction) override;
@@ skipping 25 matching lines @@
 
   ui::WindowShowState restore_show_state_ = ui::SHOW_STATE_DEFAULT;
 
   DISALLOW_COPY_AND_ASSIGN(WmWindowMus);
 };
 
 }  // namespace wm
 }  // namespace mash
 
 #endif  // MASH_WM_BRIDGE_WM_WINDOW_MUS_H_