Enable immersive fullscreen on Windows Ash.

chrome/browser/ui/views/apps/chrome_native_app_window_views.cc

Index: chrome/browser/ui/views/apps/chrome_native_app_window_views.cc
diff --git a/chrome/browser/ui/views/apps/chrome_native_app_window_views.cc b/chrome/browser/ui/views/apps/chrome_native_app_window_views.cc
index e75277baa081cb965aa1e55ea19f243ab997a0f2..5b4f723c311b80994281190743dba74d513bd473 100644
--- a/chrome/browser/ui/views/apps/chrome_native_app_window_views.cc
+++ b/chrome/browser/ui/views/apps/chrome_native_app_window_views.cc
@@ -504,17 +504,13 @@ views::NonClientFrameView* ChromeNativeAppWindowViews::CreateNonClientFrameView(
     if (!IsFrameless()) {
       ash::CustomFrameViewAsh* custom_frame_view =
           new ash::CustomFrameViewAsh(widget);
-#if defined(OS_CHROMEOS)
       // Non-frameless app windows can be put into immersive fullscreen.
-      // TODO(pkotwicz): Investigate if immersive fullscreen can be enabled for
-      // Windows Ash.
       if (ash::switches::UseImmersiveFullscreenForAllWindows()) {
         immersive_fullscreen_controller_.reset(
             new ash::ImmersiveFullscreenController());
         custom_frame_view->InitImmersiveFullscreenControllerForView(
             immersive_fullscreen_controller_.get());
       }
-#endif
       custom_frame_view->GetHeaderView()->set_context_menu_controller(this);
       return custom_frame_view;
     }