[mus+ash] Removes WmWindow from screen_dimmer and video_detector

ash/wallpaper/wallpaper_view.h

 // Copyright (c) 2012 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_WALLPAPER_WALLPAPER_VIEW_H_
 #define ASH_WALLPAPER_WALLPAPER_VIEW_H_
 
 #include <memory>
 
 #include "ui/views/context_menu_controller.h"
 #include "ui/views/view.h"
 
+namespace aura {
+class Window;
+}
+
 namespace ash {
 
 class PreEventDispatchHandler;
-class WmWindow;
 
 class WallpaperView : public views::View, public views::ContextMenuController {
  public:
   WallpaperView();
   ~WallpaperView() override;
 
  private:
   friend class WallpaperControllerTest;
 
   // Overridden from views::View:
   void OnPaint(gfx::Canvas* canvas) override;
   bool OnMousePressed(const ui::MouseEvent& event) override;
 
   // Overridden from views::ContextMenuController:
   void ShowContextMenuForView(views::View* source,
                               const gfx::Point& point,
                               ui::MenuSourceType source_type) override;
   std::unique_ptr<PreEventDispatchHandler> pre_dispatch_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(WallpaperView);
 };
 
-views::Widget* CreateWallpaper(WmWindow* root_window, int container_id);
+views::Widget* CreateWallpaper(aura::Window* root_window, int container_id);
 
 }  // namespace ash
 
 #endif  // ASH_WALLPAPER_WALLPAPER_VIEW_H_