Bug 1538765 - AwesomeBar queries are piling up and not cancelling properly (#4648)
Bug 1538765 - AwesomeBar queries are piling up and not cancelling properly (#4648)

* Bug 1538765 - AwesomeBar queries are piling up and not cancelling properly

* break retain cycle in dispatchWorkItem

flodolo/firefox-ios,flodolo/firefox-ios,st3fan/firefox-ios,flodolo/firefox-ios,mkaply/firefox-ios,justindarc/firefox-ios,StYaphet/firefox-ios,StYaphet/firefox-ios,Bunn/firefox-ios,mkaply/firefox-ios,mozilla-mobile/firefox-ios,st3fan/firefox-ios,AaronMT/firefox-ios,Acidburn0zzz/firefox-ios,StYaphet/firefox-ios,garvankeeley/firefox-ios,AaronMT/firefox-ios,mkaply/firefox-ios,Bunn/firefox-ios,st3fan/firefox-ios,mozilla-mobile/firefox-ios,Bunn/firefox-ios,Acidburn0zzz/firefox-ios,Acidburn0zzz/firefox-ios,StYaphet/firefox-ios,justindarc/firefox-ios,Bunn/firefox-ios,garvankeeley/firefox-ios,StYaphet/firefox-ios,st3fan/firefox-ios,flodolo/firefox-ios,justindarc/firefox-ios,st3fan/firefox-ios,flodolo/firefox-ios,garvankeeley/firefox-ios,justindarc/firefox-ios,AaronMT/firefox-ios,StYaphet/firefox-ios,justindarc/firefox-ios,mkaply/firefox-ios,Acidburn0zzz/firefox-ios,mozilla-mobile/firefox-ios,garvankeeley/firefox-ios,Acidburn0zzz/firefox-ios,Acidburn0zzz/firefox-ios,mozilla-mobile/firefox-ios,flodolo/firefox-ios,Bunn/firefox-ios,StYaphet/firefox-ios,AaronMT/firefox-ios,Acidburn0zzz/firefox-ios,garvankeeley/firefox-ios,mkaply/firefox-ios,AaronMT/firefox-ios,flodolo/firefox-ios,mozilla-mobile/firefox-ios,StYaphet/firefox-ios,st3fan/firefox-ios,Bunn/firefox-ios,Bunn/firefox-ios,AaronMT/firefox-ios,mozilla-mobile/firefox-ios,garvankeeley/firefox-ios,st3fan/firefox-ios,Acidburn0zzz/firefox-ios,st3fan/firefox-ios,mkaply/firefox-ios,justindarc/firefox-ios,garvankeeley/firefox-ios,justindarc/firefox-ios,mozilla-mobile/firefox-ios,AaronMT/firefox-ios,mkaply/firefox-ios