screen-capture/getdisplaymedia-settings.https.html

<!doctype html>
<meta charset=utf-8>
<title>getDisplayMedia</title>
<meta name="timeout" content="long">
<button id="button">User gesture</button>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/testdriver.js"></script>
<script src="/resources/testdriver-vendor.js"></script>
<video id="display"></video>
<script>
  'use strict';

const stopTracks = stream => stream.getTracks().forEach(track => track.stop());

async function getDisplayMedia(constraints) {
  const p = new Promise(r => button.onclick = r);
  await test_driver.click(button);
  await p;
  return navigator.mediaDevices.getDisplayMedia(constraints);
}

promise_test(async t => {
  const stream = await getDisplayMedia({video: true});
  const track = stream.getVideoTracks()[0];
  t.add_cleanup(() => stopTracks(stream));

  const settings = track.getSettings();
  const capabilities = track.getCapabilities();

  assert_true("deviceId" in settings);
  assert_equals(capabilities.deviceId, settings.deviceId);
}, "getDisplayMedia() deviceId setting and capability");

promise_test(async t => {
  const stream = await getDisplayMedia({video: true});
  const track = stream.getVideoTracks()[0];
  t.add_cleanup(() => stopTracks(stream));

  const settings = track.getSettings();
  const capabilities = track.getCapabilities();

  assert_false("facingMode" in settings);
  assert_false("facingMode" in capabilities);
}, "getDisplayMedia() and facingMode");

</script>