Bug 940408 - Rework DeferredTask to allow asynchronous tasks and support AsyncShutdown. r=Mossop
Bug 941317 - Switch Downloads.jsm to use Promise.jsm. r=enn
Bug 929067 - Canceling a download from the Downloads Panel sometimes pauses it instead. r=enn
Bug 941726 - Prevent DownloadLegacy from keeping a reference to the network request after the download is stopped. r=enn