Set the unique_event_id when converting from TouchEvent to WebTouchEvent

ui/events/test/motion_event_test_utils.cc

Index: ui/events/test/motion_event_test_utils.cc
diff --git a/ui/events/test/motion_event_test_utils.cc b/ui/events/test/motion_event_test_utils.cc
index 8cf9a7fd23ee1ef1ef9d25075d3748aab046cc0a..dbefd8caabfccca884d54ab144ca1a14c9a391c9 100644
--- a/ui/events/test/motion_event_test_utils.cc
+++ b/ui/events/test/motion_event_test_utils.cc
@@ -166,10 +166,15 @@ void MockMotionEvent::ResolvePointers() {
   }
 }
 
+void MockMotionEvent::SetPointerId(int id) {
+  DCHECK_GT(GetPointerCount(), 0U);
+  pointer(0).id = id;
+}
+
 std::string ToString(const MotionEvent& event) {
   std::stringstream ss;
   ss << "MotionEvent {"
-     << "\n ID: " << event.GetId() << "\n Action: " << event.GetAction();
+     << "\n ID: " << event.GetPointerId() << "\n Action: " << event.GetAction();
   if (event.GetAction() == MotionEvent::ACTION_POINTER_DOWN ||
       event.GetAction() == MotionEvent::ACTION_POINTER_UP)
     ss << "\n ActionIndex: " << event.GetActionIndex();