chromium/third_party/blink/web_tests/media/controls-right-click-on-timebar.html

<!DOCTYPE html>
<title>Test that right clicking on the timebar does not cause a seek.</title>
<script src="../resources/testharness.js"></script>
<script src="../resources/testharnessreport.js"></script>
<script src="media-controls.js"></script>
<video controls></video>
<script>
async_test(function(t) {
    var video = document.querySelector("video");

    video.onplaying = t.step_func(function() {
        setTimeout(t.step_func(click), 100);
    });

    video.onseeked = t.unreached_func();

    video.autoplay = true;
    video.src = "content/test.ogv";

    function click() {
        var seekCoords = mediaControlsButtonCoordinates(video, "timeline");

        eventSender.mouseMoveTo(seekCoords[0], seekCoords[1]);
        eventSender.contextClick();

        setTimeout(t.step_func_done(), 200);
    }
});
</script>