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chromium/third_party/blink/web_tests/wpt_internal/hid/resources/open-in-iframe.html 

<!DOCTYPE html>

<script src="/resources/testdriver.js"></script>
<script src="/resources/testdriver-vendor.js"></script>

<body>
  <button>
    Fake user gesture
  </button>
</body>

<script>
  test_driver.set_test_context(parent);

  window.addEventListener('message', async messageEvent => {
    switch (messageEvent.data.type) {
      case 'GetDevices':
        navigator.hid.getDevices()
            .then(devices => parent.postMessage('Success', '*'))
            .catch(err => parent.postMessage(`FAIL: ${err}`, '*'));
        break;
      case 'RequestDevice':
        await test_driver.click(document.getElementsByTagName('button')[0]);
        navigator.hid.requestDevice({filters: []})
            .then(device => parent.postMessage('Success', '*'))
            .catch(err => parent.postMessage(`FAIL: ${err}`, '*'));
        break;
      default:
        parent.postMessage(
            `FAIL: Bad message type: ${messageEvent.data.type}`, '*');
    }
  });
</script>