Case: invoke play() on an element which had its source changed (to a invalid source) after suffering from an error.
Expected result: reject the promise.
MozReview-Commit-ID: 3EDf0TpTwYb
--HG--
extra : rebase_source : 51077022d99bbb53c6eb401c4f9492cf62cc34bd
extra : source : 5d6a3ff4c554448e5f60700a876598c70273a952
Kaku Kuo