chromium/third_party/blink/web_tests/media/autoplay-from-mediastream-to-src.html

<!DOCTYPE html>
<title>Test for autoplay of video once the media stream is set to null</title>
<script src="../resources/testharness.js"></script>
<script src="../resources/testharnessreport.js"></script>
<script>
    test(function() {
        assert_true(!!window.internals && !!internals.settings,
      "This test only works when run as a layout test!");
    }, "Prerequisites to running the rest of the tests");

    internals.settings.setAutoplayPolicy('user-gesture-required');

    async_test(function(t) {
        var v = document.createElement('video');
        v.srcObject = (new AudioContext()).createMediaStreamDestination().stream;

        setTimeout(t.step_func(function() {
            v.srcObject = null;
            v.src = 'content/test.ogv';

            v.play()
                .then(t.unreached_func('The video must not play without user gesture.'))
                .catch(t.step_func_done(function() {
                    assert_true(v.paused);
                }));
        }), 0);
    }, 'Test that switching from MediaStream to src= does not autoplay.');
</script>