frameset-frameborder-inheritance-dynamic.html

<!DOCTYPE html>
<html>
<script>
testRunner.waitUntilDone();
window.onload = () => {
  requestAnimationFrame(() => {
    requestAnimationFrame(() => {
      document.body.setAttribute('frameborder', '1');
      requestAnimationFrame(() => { testRunner.notifyDone(); });
    });
  });
};
</script>
<frameset cols="50%,*" rows="50%,*" frameborder="0">
  <frame></frame>
  <frameset rows="40%,*">
    <frame></frame>
    <frame></frame>
  </frameset>
  <frame></frame>
  <frame></frame>
</frameset>
</html>

chromium/third_party/blink/web_tests/fast/frames/frameset-frameborder-inheritance-dynamic.html