delegate-fullscreen-request-recipient.html

<!DOCTYPE html>
<title>Capability Delegation of Fullscreen Requests test recipient</title>
<body>Capability Delegation of Fullscreen Requests test recipient body</body>

<script>
  const initiator = window.opener ? window.opener : window.top;
  initiator.postMessage({"type": "recipient-loaded"}, "*");

  function reportResult(msg) {
      initiator.postMessage({"type": "result", "result": msg}, "*");
  }

  document.addEventListener('fullscreenchange', async () => {
      if (document.fullscreenElement) {
          await document.exitFullscreen();
          reportResult("success");
      }
  });

  document.addEventListener('fullscreenerror', () => {
      reportResult("failure");
  });

  window.addEventListener("message", e => {
      if (e.data.type == "make-fullscreen-request") {
          document.body.requestFullscreen();
      }
  });
</script>

chromium/third_party/blink/web_tests/external/wpt/html/capability-delegation/resources/delegate-fullscreen-request-recipient.html