<html>
<head>
    <meta http-equiv="Content-Security-Policy" content="media-src 'none'">
    <script>
        if (window.testRunner) {
            testRunner.dumpAsText();
            testRunner.waitUntilDone();
        }
        function loaded() {
            alert("FAIL");
            if (window.testRunner)
                testRunner.notifyDone();
        }
        function errored() {
            alert("PASS");
            if (window.testRunner)
                testRunner.notifyDone();
        }
        function start() {
            var track = document.querySelector('track');
            track.track.mode = "hidden";
            track.setAttribute('src', 'resources/track.vtt');
        }
    </script>
</head>
<body onload="start()">
    <video>
        <track kind="captions" onload="loaded()" onerror="errored()">
    </video>
</body>
</html>