chromium/third_party/blink/web_tests/fast/events/isolated-worlds-override-keystate.html

<!DOCTYPE html>
<script>
function test()
{
    if (window.testRunner) {
        testRunner.dumpAsText();
        testRunner.dumpNavigationPolicy();
        testRunner.evaluateScriptInIsolatedWorld(1,
            "window.addEventListener('keydown', function(event) {" +
            "    var mouseEvent = new MouseEvent('click', { ctrlKey: true, metaKey: true });" +
            // event.code is something like Digit1, so code[5] gives the number.
            "    var link = document.getElementById('link' + event.code[5]);" +
            "    link.dispatchEvent(mouseEvent);" +
            "});");
        eventSender.keyDown("1");
        eventSender.keyDown("2");
    }
}
</script>
<body onload="test()">
<p>Tests that adding a ctrl modifier to a click on a link from an isolated world triggers a background tab.</p>
<a href="blank" id="link1">link</a>
<a href="blank2" id="link2" target="_blank">link</a>
</body>