chromium/third_party/blink/web_tests/gamepad/gamepad-works-after-open.html

<!DOCTYPE html>
<body>
<script src="../resources/testharness.js"></script>
<script src="../resources/testharnessreport.js"></script>
<script src="resources/gamepad-helpers.js"></script>
<script>

promise_test(async (t) => {
  // Check that gamepad connection events and getGamepads work on the parent.
  disconnectGamepads();
  let connectPromise = ongamepadconnected();
  connectGamepads(1);
  await connectPromise;
  assert_not_equals(navigator.getGamepads()[0], null);

  // Open a new window and check that gamepad connection events and getGamepads
  // still work. A message is sent on success.
  window.open('resources/check-gamepads.html');
  await new Promise(resolve => {
    window.addEventListener('message', (e) => {
      if (e.data == 'success') {
        resolve();
      }
    });
  });
}, 'gamepad API works in new window');

</script>
</body>