');
                  assert_throws_dom('InvalidStateError',
                      function() { sourceBuffer.mode = 'segments'; },
                      'Setting valid sourceBuffer.mode while still parsing media segment threw InvalidStateError.');
                  assert_equals(sourceBuffer.timestampOffset, 10.123456789);
                  assert_throws_dom('InvalidStateError',
                      function() { sourceBuffer.timestampOffset = 20.0; },
                      'Setting valid sourceBuffer.times