non-reparented-overlay-scrollbars.html

<!DOCTYPE HTML>
<meta name=fuzzy content="maxDifference=0-1;totalPixels=0-600">
<script>
if (window.internals)
    internals.useMockOverlayScrollbars();
</script>
<style>
  #scroller {
    overflow: scroll;
    width: 300px;
    height: 300px;
    margin-top: 2px;
  }

  #fixed {
    position: absolute;
    background: blue;
    left: 90px;
    width: 10px;
    height: 10px;
  }

  #scrolled {
    background: green;
    width: 80px;
    height: 500px;
  }
</style>
<div id='scroller'>
  <div id='fixed'></div>
  <div id='scrolled'></div>
</div>

chromium/third_party/blink/web_tests/compositing/overflow/non-reparented-overlay-scrollbars.html