Change ui::Event::time_stamp from TimeDelta to TimeTicks

ui/events/gestures/motion_event_aura.cc

Index: ui/events/gestures/motion_event_aura.cc
diff --git a/ui/events/gestures/motion_event_aura.cc b/ui/events/gestures/motion_event_aura.cc
index eff71e1abe2863bdb23f883db918e9f4941d68a4..473025d2f47c5037d779845a7cc6968eedaec38f 100644
--- a/ui/events/gestures/motion_event_aura.cc
+++ b/ui/events/gestures/motion_event_aura.cc
@@ -111,7 +111,7 @@ bool MotionEventAura::OnTouch(const TouchEvent& touch) {
   UpdateCachedAction(touch);
   set_unique_event_id(touch.unique_event_id());
   set_flags(touch.flags());
-  set_event_time(touch.time_stamp() + base::TimeTicks());
+  set_event_time(touch.time_stamp());
   return true;
 }