<!DOCTYPE html>

<html>
<head>
<style>
    #box {
        width: 100px;
        height: 100px;
        margin: 10px;
        padding: 10px;
        box-sizing: border-box;
        background-color: silver;
        -webkit-transform-origin: top left;
    }
    
    .animating {
        -webkit-animation: scale 100000000s infinite linear;
    }
    
    @-webkit-keyframes scale {
        from { -webkit-transform: scale(1.5); }
        to   { -webkit-transform: scale(3); }
    }
</style>
    <script>
        if (window.testRunner) {
            testRunner.dumpAsText();
            testRunner.waitUntilDone();
        }

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

            if (window.testRunner)
                testRunner.notifyDone();
        }
        
        function doTest()
        {
            var box = document.getElementById('box');
            box.addEventListener('webkitAnimationStart', dumpLayers, false);
            box.classList.add('animating');
        }
        window.addEventListener('load', doTest, false);
    </script>
</head>
<body>

    <div id="box">Box</div>

    <pre id="layers">Layer tree goes here when testing</pre>
</body>
</html>