Re-apply "Explicitly disable multiprocess Firefox"
Re-apply "Explicitly disable multiprocess Firefox"

9584f6d1be9f80e6e688de42d263b72d75db3054

madand/pentadactyl-pm,madand/pentadactyl-pm,madand/pentadactyl-pm,madand/pentadactyl-pm,madand/pentadactyl-pm,madand/pentadactyl-pm