Reenable synthesized mouse event on win aura

ui/aura/root_window.cc

Index: ui/aura/root_window.cc
diff --git a/ui/aura/root_window.cc b/ui/aura/root_window.cc
index fa7760f51e49d8b9b8f251ed79ddf460fcfa3d26..0e5f1b31b4c203de76b772145e2dd6654f76af60 100644
--- a/ui/aura/root_window.cc
+++ b/ui/aura/root_window.cc
@@ -992,8 +992,6 @@ void RootWindow::SynthesizeMouseMoveEvent() {
   if (!synthesize_mouse_move_)
     return;
   synthesize_mouse_move_ = false;
-#if !defined(OS_WIN)
-  // Temporarily disabled for windows. See crbug.com/112222.
   gfx::Point3F point(GetLastMouseLocationInRoot());
   float scale = ui::GetDeviceScaleFactor(layer());
   gfx::Transform transform;
@@ -1010,7 +1008,6 @@ void RootWindow::SynthesizeMouseMoveEvent() {
                        ui::EF_IS_SYNTHESIZED);
   event.set_system_location(Env::GetInstance()->last_mouse_location());
   OnHostMouseEvent(&event);
-#endif
 }
 
 }  // namespace aura