<!DOCTYPE html> <!-- webkit-test-runner [ AsyncOverflowScrollingEnabled=true AsyncFrameScrollingEnabled=true ] -->
<html>
<style>
    iframe { 
        width: 500px;
        height: 320px;
        border: 5px solid gray;
        padding: 12px;
    }

</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>
    <iframe srcdoc="
    <style>
        body { height: 1000px; }
    </style>
    This is a scrollable subframe.
    "></iframe>

<pre id="results"></pre>
</body>
</html>