chromium/chrome/test/data/webrtc/webrtc_getdisplaymedia_embedded_document.html

<!DOCTYPE html PUBLIC "-//IETF//DTD HTML//EN">
<html>
  <head>
    <title>WebRTC Automated Test</title>
    <script type="text/javascript" src="test_functions.js"></script>
  </head>
  <body>
    <script>
      async function runTestedFunction(constraints) {
        try {
          await navigator.mediaDevices.getDisplayMedia(constraints);
          window.parent.postMessage("embedded-capture-success", "*");
        } catch (e) {
          window.parent.postMessage("embedded-capture-failure", "*");
        }
      }

      window.addEventListener("message", (event) => {
        runTestedFunction(event.data);
      });
    </script>
  </body>
</html>