Bug 856281 - Fixed HAVE_NATIVE_UNWIND definition. r=ehsan

--HG--
extra : rebase_source : d142eb85d08563a024e84a9954a890eb01087135
Bug 850210 - Part 3. Update DownloadLastDir usage of removePrefsByName to nsIContentPrefService2. r=adw
Bug 854299 - Part 1. Split nsExternalAppHandler::SaveToDisk in two parts to make second part async. r=bz sr=roc
Bug 854299 - Part 2. Update DownloadLastDir.getFile. r=adw
Bug 854299 - Part 3. Change tests accordingly to support operations that are now async. r=me
* * *
imported patch testfix
Bug 854299 - Part 4. Add a callback function to contentAreaUtils's getTargetFile. r=adw
Bug 854299 - Part 5. Make nsHelperAppDlg.promptForSaveToFileAsync actually async. r=bz