<!DOCTYPE html>
<html>
<head>
    <style>
        div {
            position: relative;
            height: 100px;
            width: 100px;
        }
        .big {
            width: 2048px;
            height: 2048px;
        }
        .media-controls {
            -webkit-transform: translate3d(0, 0, 0); /* The element has to request a layer for the appearance to work */
        }
        .dark {
            -webkit-appearance: media-controls-dark-bar-background;
        }
        .light {
            -webkit-appearance: media-controls-light-bar-background;
        }
    </style>
    <script>
        if (window.testRunner) {
            testRunner.dumpAsText();
            testRunner.waitUntilDone();
        }

        function change()
        {
            var elements = document.querySelectorAll(".media-controls");
            for (var i = 0; i < elements.length; ++i)
                elements[i].classList.add("big");
            setTimeout(dumpLayers, 0);
        }

        function dumpLayers()
        {
            var layersResult = document.getElementById('layers');
            if (window.testRunner) {
                layersResult.innerText = window.internals.layerTreeAsText(document);
                testRunner.notifyDone();
            }
        }
        window.addEventListener('load', change, false)
    </script>
</head>
<body>
    <div class="media-controls dark">
    </div>
    <div class="media-controls light">
    </div>
<pre id="layers"></pre>
</body>
</html>