<!DOCTYPE html>

<html>
<head>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <style>
        .box {
            margin: 20px;
            width: 100px;
            height: 0px;
            overflow: hidden;
            background-color: blue;
            -webkit-transform: translateZ(0);
        }
        
        .box.changed {
            height: 100px;
        }
    </style>
    <script>
        if (window.testRunner) {
            testRunner.dumpAsText();
            testRunner.waitUntilDone();
        }

        function doTest()
        {
            window.setTimeout(function() {
                document.body.offsetWidth;

                document.getElementById('box').classList.add('changed');

                if (window.internals)
                    document.getElementById('layers').innerText = internals.layerTreeAsText(document, internals.LAYER_TREE_INCLUDES_VISIBLE_RECTS)

                if (window.testRunner)
                    testRunner.notifyDone();

            }, 0);

        }
        window.addEventListener('load', doTest, false);
    </script>

</head>
<body>
    <div id="box" class="box">Content</div>
<pre id="layers">Layer tree goes here when testing</pre>
</body>
</html>