Enable immersive fullscreen on Windows Ash.

ash/frame/custom_frame_view_ash.cc

Index: ash/frame/custom_frame_view_ash.cc
diff --git a/ash/frame/custom_frame_view_ash.cc b/ash/frame/custom_frame_view_ash.cc
index 964020b8a48c9cbe0b3492e30bd5e3b5ef243ed6..b67f867ee50d501d7bdd8cb07e3a8c0babb41db4 100644
--- a/ash/frame/custom_frame_view_ash.cc
+++ b/ash/frame/custom_frame_view_ash.cc
@@ -55,9 +55,6 @@ class CustomFrameViewAshWindowStateDelegate
       ash::wm::WindowState* window_state,
       ash::CustomFrameViewAsh* custom_frame_view)
       : window_state_(NULL) {
-#if defined(OS_CHROMEOS)
-    // TODO(pkotwicz): Investigate if immersive fullscreen can be enabled for
-    // Windows Ash.
     immersive_fullscreen_controller_.reset(
         new ash::ImmersiveFullscreenController);
     custom_frame_view->InitImmersiveFullscreenControllerForView(
@@ -71,7 +68,6 @@ class CustomFrameViewAshWindowStateDelegate
     window_state_ = window_state;
     window_state_->AddObserver(this);
     window_state_->window()->AddObserver(this);
-#endif
   }
   virtual ~CustomFrameViewAshWindowStateDelegate() {
     if (window_state_) {