Bug 873914 - Allow selecting profiled thread. r=snorp

--HG--
extra : rebase_source : 6623126a111b23f8871af1a2e64d077b67cb0930
Bug 838331 - Add MP3 to codec list for Firefox OS. r=doublec
Bug 883784 - [Workers] Support URL.createObjectURL from a worker created by a jsm. r=bent