<!DOCTYPE html>
<html>
<head>
    <style>
        html {
            visibility: hidden;
        }
    </style>
    <script>
        if (window.testRunner) {
            testRunner.dumpAsText();
            testRunner.waitUntilDone();
        }

        function doTest()
        {
            requestAnimationFrame(() => {
                document.documentElement.style.visibility = 'visible';

                if (window.internals)
                    document.getElementById('layers').textContent = window.internals.layerTreeAsText(document, internals.LAYER_TREE_INCLUDES_ROOT_LAYER_PROPERTIES);

                if (window.testRunner)
                    testRunner.notifyDone();
            });
        }
        window.addEventListener('load', doTest, false);
    </script>
</head>
<body>
<p>This text should be visible.</p>
<pre id="layers"></pre>
</body>
</html>