<!DOCTYPE html> <!-- webkit-test-runner [ AsyncOverflowScrollingEnabled=true ] -->
<html>
<head>
    <style>
        .scroller {
            position: relative;
            width: 300px;
            height: 300px;
            margin: 50px;
            border: 15px solid gray;
            overflow: scroll;
            box-shadow: 0 0 10px rgba(0, 0, 0, 0.5);
        }
        
        .scroller > .scroller {
            height: 500px;
        }

        .filler {
            width: 100px;
            height: 250px;
            background-color: silver;
        }

        .box {
            position: absolute;
            width: 100%;
            height: 100px;
            background-color: white;
            z-index: 2;
            transform: translateZ(0);
        }

        .upper.box {
            top: 150px;
            left: 150px;
            width: 240px;
            background-color: rgba(134, 123, 28, 0.75)
        }

        .interleaved {
            position: absolute;
            top: 220px;
            left: 250px;
            width: 200px;
            height: 200px;
            background-color: rgba(80, 160, 80, 0.8);
            z-index: 1;
            transform: translateZ(0);
        }
    </style>
    <script>
        if (window.testRunner)
            testRunner.dumpAsText();

        if (window.internals)
            internals.setUsesOverlayScrollbars(true);

        window.addEventListener('load', () => {
            if (window.internals)
                document.getElementById('layers').innerText = window.internals.layerTreeAsText(document);
        }, false);
    </script>
</head>
<body>
    <div class="scroller">
        <div class="scroller">
            <div class="filler"></div>
            <div class="box">
                overlaps scrollbar
            </div>
            <div class="filler"></div>
            <div class="filler"></div>
        </div>
    </div>
    <div class="upper box"></div>
    <div class="interleaved"></div>
<pre id="layers"></pre>
</body>
</html>