event_sender should include a timeStamp when dispatching keyboard events

components/test_runner/event_sender.cc

Index: components/test_runner/event_sender.cc
diff --git a/components/test_runner/event_sender.cc b/components/test_runner/event_sender.cc
index 4ead1cdc25f206598cd4d979bb61a94db0cca582..b648b89512f76e0acd0af237eee2b9f5924c5a56 100644
--- a/components/test_runner/event_sender.cc
+++ b/components/test_runner/event_sender.cc
@@ -1396,6 +1396,7 @@ void EventSender::KeyDown(const std::string& code_str,
   // Windows event flow; on other platforms we create a merged event and test
   // the event flow that that platform provides.
   WebKeyboardEvent event_down;
+  event_down.timeStampSeconds = GetCurrentEventTimeSec();
   event_down.type = WebInputEvent::RawKeyDown;
   event_down.modifiers = modifiers;
   event_down.windowsKeyCode = code;