chromium/third_party/blink/web_tests/compositing/overflow/scroller-with-border-radius.html

<!DOCTYPE HTML>
<script src="../../resources/run-after-layout-and-paint.js"></script>
<style>
#scroller {
    overflow: scroll;
    height: 300px;
    width: 300px;
    background-color: red;
}

#scrolled {
    height: 1000px;
    width: 250px;
    background-color: green;
}

#fixed {
    position: fixed;
    height: 100px;
    width: 100px;
    background-color: green;
    top: 400px;
    left: 100px;
}
</style>
<div id="scroller">
    <div id="scrolled"></div>
    <div id="fixed"></div>
</div>
<script>
if (window.internals)
    internals.settings.setPreferCompositingToLCDTextEnabled(true);

onload = function() {
    runAfterLayoutAndPaint(function() {
        scroller.style.borderRadius = '5px';
    }, true);
};
</script>