chromium/third_party/blink/web_tests/compositing/overflow/clip-parent-reset.html

<!DOCTYPE html>
<div style="width:150px; height:150px; overflow:hidden; opacity:0.8; background:red;">
    <div style="width:100px; height:100px; overflow:hidden;">
        <div id="bug" style="width:200px; height:200px; position:absolute; will-change:transform; background:green;">
        </div>
    </div>
</div>
This test verifies the clip parent of a layer gets correctly reset when it gained a non-composited clip.
<script src="../../resources/run-after-layout-and-paint.js"></script>
<script>
runAfterLayoutAndPaint(function() {
    document.getElementById("bug").style.position = "static";
}, true);
</script>