chromium/third_party/blink/web_tests/external/wpt/css/css-contain/content-visibility/content-visibility-074.html

<!doctype HTML>
<html class="reftest-wait">
<meta charset="utf8">
<title>CSS Content Visibility: toggling auto with composited descedant</title>
<link rel="author" title="Vladimir Levin" href="mailto:[email protected]">
<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
<link rel="match" href="content-visibility-074-ref.html">
<meta name="assert" content="after toggling content-visibility auto a few times, composited descedant is visible.">

<script src="/common/reftest-wait.js"></script>

<style>
#a { will-change: transform; }
#b { height: 15000px; }
#c {
  width: 800px;
  height: 600px;
}
#d {
  will-change: transform;
  top: 0px;
  width: 500px;
  height: 500px;
  background: green;
}
.auto {
  content-visibility: auto;
}

</style>

<div id="a">
</div>
<div id="b">
  <div id="c" class=auto>
    <div id="d"></div>
    </div>
  </div>
</div>

<script>
function runTest(step) {
  if (step % 2 == 0) {
    requestAnimationFrame(() => runTest(step + 1));
    return;
  }

  switch(step) {
    case 1:
      document.getElementById("c").classList.remove("auto");
      break;
    case 3:
      document.getElementById("c").classList.add("auto");
      break;
    case 5:
      document.getElementById("c").classList.remove("auto");
      break;
    case 7:
      document.getElementById("c").classList.add("auto");
      break;
    case 9:
      takeScreenshot();
      return;
  }
  requestAnimationFrame(() => runTest(step + 1));
}

window.onload = () => requestAnimationFrame(() => runTest(0));
</script>