mozilla-release/dom/media/tests/mochitest/test_1488832.html

<!DOCTYPE HTML>
<html>
<head>
<script type="application/javascript" src="mediaStreamPlayback.js"></script>
</head>
<body>
<iframe id="testframe"></iframe>
<script>
"use strict";

createHTML({
  title: "gUM shutdown race",
  bug: "1488832"
});

runTest(async () => {
  testframe.srcdoc = `
  <html>
  <head>
  <script>
  function start() {
    for (let i = 0; i < 16; i++) {
      window.navigator.mediaDevices.getUserMedia({video: true})
      setTimeout('location.reload()', 100)
    }
  }
  document.addEventListener('DOMContentLoaded', start)
  </` + `script>
  </head>
  </html>`;

  await wait(10000);
  testframe.srcdoc = "";
});
</script>
</body>
</html>