[mus+ash] Removes WmWindow from screen_dimmer and video_detector

ash/high_contrast/high_contrast_controller.cc

Index: ash/high_contrast/high_contrast_controller.cc
diff --git a/ash/high_contrast/high_contrast_controller.cc b/ash/high_contrast/high_contrast_controller.cc
index 2149ad323f64bfc8ff883e59c7cc8d76897fe90d..ebe2176a2e2f19037ec5dda8062949011ef0a1c9 100644
--- a/ash/high_contrast/high_contrast_controller.cc
+++ b/ash/high_contrast/high_contrast_controller.cc
@@ -34,8 +34,8 @@ void HighContrastController::UpdateDisplay(aura::Window* root_window) {
   root_window->layer()->SetLayerInverted(enabled_);
 }
 
-void HighContrastController::OnRootWindowAdded(WmWindow* root_window) {
-  UpdateDisplay(WmWindow::GetAuraWindow(root_window));
+void HighContrastController::OnRootWindowAdded(aura::Window* root_window) {
+  UpdateDisplay(root_window);
 }
 
 }  // namespace ash