composited-background-on-both-layers.html

<!DOCTYPE html>
<div id="target"
     style="will-change: transform; overflow: scroll; background: red;
            width: 200px; height: 200px; border: 20px dashed black">
  <div style="height: 3000px"></div>
</div>
<script src="../resources/text-based-repaint.js"></script>
<script>
function repaintTest() {
  target.style.background = 'green';
}
onload = runRepaintAndPixelTest;
</script>

chromium/third_party/blink/web_tests/paint/invalidation/background/composited-background-on-both-layers.html