<!DOCTYPE html>

<html>
<head>
    <style>
        .box {
          width: 100px;
          height: 100px;
          background-color: silver;
        }
        
        .backface-hidden {
            -webkit-backface-visibility: hidden;
        }
    </style>
    <script>
        if (window.testRunner)
            testRunner.dumpAsText();

        function dumpLayers()
        {
            var layersResult = document.getElementById('layers');
            if (window.testRunner)
                layersResult.innerText = window.internals.layerTreeAsText(document);

        }
        window.addEventListener('load', dumpLayers, false)
    </script>
</head>
<body>
    <p>Should be no layers here.</p>
    <div class="backface-hidden box"></div>
<pre id="layers"></pre>
</body>
</html>