bug 1077595 - Use DataStoreChangeEvents to update Download API Manager cache up to date. Move tracking of active downloads into StatusBar instead of DownloadNotifications. r=kgrandon (system, shared), mhenretty (statusbar), arthurcc (settings)
Merge pull request #25589 from nullaus/bug1077595

bug 1077595 - Use DataStoreChangeEvents to update Download API Manager c...