chromium/content/test/data/accessibility/css/iframe-hidden.html

<!--
@WIN-ALLOW:ia2_hypertext=*
@NO-LOAD-EXPECTED:nested-frame.html
@NO-LOAD-EXPECTED:box.html
@WAIT-FOR:done
-->
<main>
  <p>Before visibility:collapse iframes</p>
  <div style="visibility:collapse">
    <iframe src="accessibility/html/frame/nested-frame.html">
    </iframe>
  </div>
  <p>After visibility:collapse iframes</p>
</main>
<div>
  <hr>
</div>
<footer>
  <p>Before display:none iframes</p>
  <div style="display:none">
    <iframe src="accessibility/html/frame/nested-frame.html">
    </iframe>
  </div>
  <p>After display:none iframes</p>
</footer>

<script>
  document.querySelector('iframe').addEventListener('load', () => {
    requestAnimationFrame(() => {
      requestAnimationFrame(() => {
        document.title = 'done';
      });
    });
  });
</script>