Bug 843971: Add MediaManager function to report what a window is capturing r=smaug a=lsblakk ba=jorgev
Bug 843971 - Update browser-specific indicators when content gains or releases access to devices. r=dolske  a=lsblakk
Bug 843971: fix backend for GUM a/v notification in opt builds r=derf a=lsblakk ba=jorgev