Enable immersive fullscreen on Windows Ash.

ash/wm/window_state.cc

Index: ash/wm/window_state.cc
diff --git a/ash/wm/window_state.cc b/ash/wm/window_state.cc
index 8f69a364ff245437812a51ea3c476063947c2b45..b464f04c35e2dfbc7e5aed55bab4e16e91f1b8f3 100644
--- a/ash/wm/window_state.cc
+++ b/ash/wm/window_state.cc
@@ -96,14 +96,12 @@ WindowState::WindowState(aura::Window* window)
       ignore_property_change_(false),
       current_state_(new DefaultState(ToWindowStateType(GetShowState()))) {
   window_->AddObserver(this);
-#if defined(OS_CHROMEOS)
   // NOTE(pkotwicz): Animating to immersive fullscreen does not look good. When
   // switches::UseImmersiveFullscreenForAllWindows() returns true, most windows
   // can be put into immersive fullscreen. It is not worth the added complexity
   // to only animate to fullscreen if the window is put into immersive
   // fullscreen.
   animate_to_fullscreen_ = !switches::UseImmersiveFullscreenForAllWindows();
-#endif
 }
 
 WindowState::~WindowState() {