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

ui/message_center/views/notification_view_unittest.cc

Index: ui/message_center/views/notification_view_unittest.cc
diff --git a/ui/message_center/views/notification_view_unittest.cc b/ui/message_center/views/notification_view_unittest.cc
index 053feeca09c2fd3ceede886353f08880de06ba9c..491900fd0d1f9886861c3daf71ff2838bcee46fc 100644
--- a/ui/message_center/views/notification_view_unittest.cc
+++ b/ui/message_center/views/notification_view_unittest.cc
@@ -38,7 +38,7 @@ namespace {
 std::unique_ptr<ui::GestureEvent> GenerateGestureEvent(ui::EventType type) {
   ui::GestureEventDetails detail(type);
   std::unique_ptr<ui::GestureEvent> event(
-      new ui::GestureEvent(0, 0, 0, base::TimeDelta(), detail));
+      new ui::GestureEvent(0, 0, 0, base::TimeTicks(), detail));
   return event;
 }
 
@@ -46,7 +46,7 @@ std::unique_ptr<ui::GestureEvent> GenerateGestureVerticalScrollUpdateEvent(
     int dx) {
   ui::GestureEventDetails detail(ui::ET_GESTURE_SCROLL_UPDATE, dx, 0);
   std::unique_ptr<ui::GestureEvent> event(
-      new ui::GestureEvent(0, 0, 0, base::TimeDelta(), detail));
+      new ui::GestureEvent(0, 0, 0, base::TimeTicks(), detail));
   return event;
 }