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

ash/drag_drop/drag_drop_controller_unittest.cc

Index: ash/drag_drop/drag_drop_controller_unittest.cc
diff --git a/ash/drag_drop/drag_drop_controller_unittest.cc b/ash/drag_drop/drag_drop_controller_unittest.cc
index 670cc6707cd3b39b24f685e3d491f71745cda099..a4865cd4fc2b23f22476a0effe4eb464d768c3ad 100644
--- a/ash/drag_drop/drag_drop_controller_unittest.cc
+++ b/ash/drag_drop/drag_drop_controller_unittest.cc
@@ -1077,7 +1077,7 @@ TEST_F(DragDropControllerTest, TouchDragDropCompletesOnFling) {
   gfx::Point mid = start + gfx::Vector2d(drag_view->bounds().width() / 6, 0);
   gfx::Point end = start + gfx::Vector2d(drag_view->bounds().width() / 3, 0);
 
-  base::TimeDelta timestamp = ui::EventTimeForNow();
+  base::TimeTicks timestamp = ui::EventTimeForNow();
   ui::TouchEvent press(ui::ET_TOUCH_PRESSED, start, 0, timestamp);
   generator.Dispatch(&press);