composite-change-after-scroll-preserves-stacking-order.html

<!doctype HTML>
<link rel="author" title="Chris Harrelson" href="[email protected]">
<link rel="match" href="composite-change-after-scroll-preserves-stacking-order-ref.html">
<link rel="help" href="https://www.w3.org/TR/CSS2/zindex.html"/>
<script src="/common/reftest-wait.js"></script>
<script src="/web-animations/testcommon.js"></script>
<style>
    #one, #two {
        width: 200px; height: 200px; background: lightblue; position: relative
    }
    #one {
        background: lightblue
    }
    #two {
        background: lightgray;
        margin-top: -200px;
    }
</style>
<html class=reftest-wait>
  <div id=scroller style="overflow: scroll; width: 300px; height: 300px; will-change: transform">
    <div id=one></div>
    <div id=two></div>
    <div id=spacer style="width: 50px; height: 5000px"></div>
  </div>
</html>
<script>
  onload = () => {
    waitForAnimationFrames(2).then(() => {
      scroller.scrollBy(0, 1000);
      waitForAnimationFrames(2).then(() => {
        one.style = 'will-change: transform';
        waitForAnimationFrames(2).then(() => {
          scroller.scrollBy(0, -1000);
          takeScreenshot();
        });
      });
    });
  };
</script>

chromium/third_party/blink/web_tests/external/wpt/css/CSS2/stacking-context/composite-change-after-scroll-preserves-stacking-order.html