Set the unique_event_id when converting from TouchEvent to WebTouchEvent

ui/events/gesture_detection/motion_event_generic_unittest.cc

Index: ui/events/gesture_detection/motion_event_generic_unittest.cc
diff --git a/ui/events/gesture_detection/motion_event_generic_unittest.cc b/ui/events/gesture_detection/motion_event_generic_unittest.cc
index a67646b24f57a5f94a574cada63b75be91afc4d5..f1e9fb2a2830b5c5cf0b4f72b65c4d3e7080973a 100644
--- a/ui/events/gesture_detection/motion_event_generic_unittest.cc
+++ b/ui/events/gesture_detection/motion_event_generic_unittest.cc
@@ -27,9 +27,6 @@ TEST(MotionEventGenericTest, Basic) {
   EXPECT_EQ(2.3f, event.GetX(2));
   EXPECT_EQ(-3.7f, event.GetY(2));
 
-  event.set_id(1);

[tdresser, 2015/04/16 17:33:34]

Shouldn't we still be able to verify that the pointer ids work correctly?

[lanwei, 2015/04/20 19:58:59]

Done.

-  EXPECT_EQ(1, event.GetId());
-
   event.set_action(MotionEvent::ACTION_POINTER_DOWN);
   EXPECT_EQ(MotionEvent::ACTION_POINTER_DOWN, event.GetAction());
 
@@ -78,7 +75,6 @@ TEST(MotionEventGenericTest, Clone) {
   MotionEventGeneric event(MotionEvent::ACTION_DOWN,
                            base::TimeTicks::Now(),
                            PointerProperties(8.3f, 4.7f, 2.f));
-  event.set_id(1);
   event.set_button_state(MotionEvent::BUTTON_PRIMARY);
 
   scoped_ptr<MotionEvent> clone = event.Clone();
@@ -110,7 +106,6 @@ TEST(MotionEventGenericTest, Cancel) {
   MotionEventGeneric event(MotionEvent::ACTION_UP,
                            base::TimeTicks::Now(),
                            PointerProperties(8.7f, 4.3f, 1.f));
-  event.set_id(2);
   event.set_button_state(MotionEvent::BUTTON_SECONDARY);
 
   scoped_ptr<MotionEvent> cancel = event.Cancel();