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 da5b8fcbde2bf9a3b681ed2498af79d09a951ebe..965f6a0a9948f0e15d9e3bdad68dba235e95aba8 100644
--- a/ui/events/gestures/motion_event_aura.cc
+++ b/ui/events/gestures/motion_event_aura.cc
@@ -100,7 +100,7 @@ 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;
 }