track-messageport-postmessage-cross-origin-iframe.html

<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>Verify that postmessage tasks can be properly tracked.</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/common/get-host-info.sub.js"></script>
<script src="resources/task-ids.js"></script>
</head>
<body>
<script>
promise_test(t => {
  const scriptId = initializeTaskId();
  const channel = new MessageChannel();
  const {REMOTE_ORIGIN} = get_host_info();

  const frame = document.createElement("iframe");
  frame.addEventListener("load", () => {
    frame.contentWindow.postMessage("port", "*", [channel.port2]);
  });
  frame.src = `${REMOTE_ORIGIN}/wpt_internal/task-tracking/resources/messageport-postmessage-iframe.html`;
  document.body.appendChild(frame);

  return new Promise((resolve, reject) => {
    channel.port1.onmessage = e => {
      try {
        assert_not_equals(scheduler.taskId, e.data);
        resolve();
      } catch(e) {
        reject(e);
      }
    }
  });
}, "Cross-origin iframe MessagePort postMessage task properly detects its parent task.");

</script>
</body>
</html>

chromium/third_party/blink/web_tests/wpt_internal/task-tracking/track-messageport-postmessage-cross-origin-iframe.html