Fix buffer.viewSourceExternally.
Fix buffer.viewSourceExternally.

--HG--
extra : rebase_source : 46750802d4fb7477fef5b96b0779842f946c37b2

Kjwon15/dactyl,nathyong/dactyl,nathyong/dactyl,airodactyl/dactyl,madand/pentadactyl-pm,madand/pentadactyl-pm,Kjwon15/dactyl,Kjwon15/dactyl,airodactyl/dactyl,nathyong/dactyl,invl/dactyl,5digits/dactyl,madand/pentadactyl-pm,nathyong/dactyl,Kjwon15/dactyl,madand/pentadactyl-pm,airodactyl/dactyl,airodactyl/dactyl,invl/dactyl,5digits/dactyl,nathyong/dactyl,Kjwon15/dactyl,Kjwon15/dactyl,moonshadow/dactyl,moonshadow/dactyl,5digits/dactyl,invl/dactyl,moonshadow/dactyl,invl/dactyl,invl/dactyl,madand/pentadactyl-pm,5digits/dactyl,moonshadow/dactyl,invl/dactyl,5digits/dactyl,airodactyl/dactyl,5digits/dactyl,airodactyl/dactyl,madand/pentadactyl-pm,moonshadow/dactyl,moonshadow/dactyl,nathyong/dactyl