<!DOCTYPE html>
<html>

<script>
if (window.testRunner) {
    testRunner.waitUntilDone();
    testRunner.dumpAsText();
}

function srcDocModify() {
    iframe.srcdoc = "";
    if (window.testRunner)
        testRunner.notifyDone();
}
function runTest() {
    document = iframe.contentDocument;
    document.execCommand("selectAll", false);
    window.requestAnimationFrame(srcDocModify);
}
</script>

<body>
<p>This test passes if there is no crash.</p>
<iframe id="iframe" src="data:text/html,foo"></iframe>
<video onloadstart="runTest()">
<source>
</body>
</html>