chromium/third_party/blink/web_tests/media/controls/captions-menu-always-visible.html

<!DOCTYPE html>
<title>Captions menu always visible</title>
<script src="../media-controls.js"></script>
<script src="../../resources/run-after-layout-and-paint.js"></script>
<style>
  .container {
    overflow: hidden;
  }
  video {
    position: relative;
    left: 200px;
    width: 100px;
  }
</style>
<video preload="auto" controls muted controlslist=nofullscreen></video>
<script>
  function waitForVideoPresentation(video) {
    return new Promise(resolve => {
      video.requestVideoFrameCallback(resolve);
    });
  }
  if (window.testRunner)
    testRunner.waitUntilDone();

  var video = document.querySelector('video');
  enableTestMode(video);
  video.src = '../content/test.ogv';
  video.addTextTrack('captions', 'foo');
  video.addTextTrack('captions', 'bar');
  let videoPresentation = waitForVideoPresentation(video);

  video.addEventListener('loadedmetadata', () => {
    var coords =
        mediaControlsButtonCoordinates(video, "toggle-closed-captions-button");
    clickAtCoordinates(coords[0], coords[1]);

    // Disabling pointer events on the text track menu to avoid a flakyness with
    // :hover sometimes applying.
    textTrackMenu(video).style = 'pointer-events: none;';

    videoPresentation.then(() => {
      runAfterLayoutAndPaint(() => {
        testRunner.notifyDone();
      });
    });
  });
</script>