<!DOCTYPE html> <!-- webkit-test-runner [ AsyncOverflowScrollingEnabled=true ] -->
<html>
<style>
    * {
        box-sizing: border-box;
    }
    
    .event {
        position: absolute;
        background-color: silver;
        width: 200px;
        height: 200px;
        border: 1px solid black;
        margin: 100px;
        will-change: transform;
    }
    .child {
        position: relative;
        background-color: silver;
        left: -75px;
        top: -50px;
        width: 50px;
        height: 50px;
        border: 1px solid black;
        box-shadow: -20px -20px 0px gray;
    }
</style>
<script>
window.onload = () => {
    if (window.testRunner)
        testRunner.dumpAsText();

    if (window.internals)
        results.innerText = internals.layerTreeAsText(document, internals.LAYER_TREE_INCLUDES_EVENT_REGION);
}
</script>
<body>
<div class="event" onwheel="(void)0">
    <div class="child"></div>
</div>
<pre id="results"></pre>
</body>
</html>