<!DOCTYPE html>
<html>
<head>
    <style>
        .underlay {
            position: fixed;
            width: 1024px;
            height: 1042px;
            background-color: rgba(0, 0, 0, 0.9);
        }
        
        .image {
            position: relative;
            width: 100px;
            height: 100px;
            background-color: green;
        }
    </style>
    <script>
        if (window.testRunner)
            testRunner.dumpAsText();

        if (window.internals)
            window.internals.settings.setAcceleratedCompositingForFixedPositionEnabled(true);

        function doTest()
        {
            if (window.eventSender)
                eventSender.scalePageBy(3, 3);

            if (window.testRunner)
              document.getElementById('layers').innerText = window.internals.layerTreeAsText(document);
        }
        window.addEventListener('load', doTest, false);
    </script>
</head>
<body>
    <div class="underlay"></div>
    <div class="image">Image</div>
<pre id="layers"></pre>
</body>
</html>