[mus+ash] Removes WmWindow from screen_dimmer and video_detector

ash/wallpaper/wallpaper_controller.h

Index: ash/wallpaper/wallpaper_controller.h
diff --git a/ash/wallpaper/wallpaper_controller.h b/ash/wallpaper/wallpaper_controller.h
index 2ca60ed58577c8a87c81339b42d9fd36ada9966a..3c5ad06c15bb8b27ce67d63f4cfef636e5a9c394 100644
--- a/ash/wallpaper/wallpaper_controller.h
+++ b/ash/wallpaper/wallpaper_controller.h
@@ -94,7 +94,7 @@ class ASH_EXPORT WallpaperController
   void OnDisplayConfigurationChanged() override;
 
   // ShellObserver:
-  void OnRootWindowAdded(WmWindow* root_window) override;
+  void OnRootWindowAdded(aura::Window* root_window) override;
 
   // SessionObserver:
   void OnSessionStateChanged(session_manager::SessionState state) override;
@@ -137,7 +137,7 @@ class ASH_EXPORT WallpaperController
   friend class WallpaperControllerTest;
 
   // Creates a WallpaperWidgetController for |root_window|.
-  void InstallDesktopController(WmWindow* root_window);
+  void InstallDesktopController(aura::Window* root_window);
 
   // Creates a WallpaperWidgetController for all root windows.
   void InstallDesktopControllerForAllWindows();