chromium/third_party/blink/web_tests/paint/invalidation/compositing/new-stacking-context.html

<!DOCTYPE html>
<style>::-webkit-scrollbar {display: none;}</style>
<script src="../resources/text-based-repaint.js"></script>
<script>
if (window.internals)
  internals.settings.setPreferCompositingToLCDTextEnabled(true);
function repaintTest() {
  target.style.opacity = '.5';
  target.style.backgroundColor = 'green';
}
onload = runRepaintAndPixelTest;
</script>
<div style="width: 100px; height: 100px; overflow: scroll">
  <div id="target" style="width: 200px; height: 200px; background: red; overflow: hidden"></div>
  <div></div>
</div>