chromium/third_party/blink/manual_tests/scroll-after-layer-removal.html

<!DOCTYPE html>
<style>
#scroll {
    width: 100px;
    height: 100px;
    overflow: scroll;
}
.trans { will-change: transform; }
#space { height: 1000px; }
</style>
<p>This test verifies that cc does not intercept scroll events after a scroller is un-promoted.</p>
<p>It passes if the box can be scrolled with the mouse wheel.</p>
<p>On high DPI, pass --disable-prefer-compositing-to-lcd-text for a meaningful test.</p>
<div id="scroll" class="trans"><div id="space"></div>
</div>
<script>
setTimeout(function() { document.querySelector('#scroll').classList.remove('trans'); }, 1000);
</script>