<!doctype html>
<html>
<head>
<meta charset=utf-8>
<title></title>
<script src=/resources/testharness.js></script>
<script src=/resources/testharnessreport.js></script>
</head>
<body>
<script>
<!--
promise_test(t => {
  return new Promise((resolve) => {
    let ifr = document.createElement("iframe");
    ifr.src =
      "data:text/html,<script> let bc = new BroadcastChannel(\"test\");" +
      "bc.onmessage = (e) => {" +
      "  if (e.data == \"ping\") bc.postMessage('pong');"+
      "  else parent.postMes