Originally, RDD reused the GPU process selector since they were
using all the same services, and it reduced the number of places
that had to be touched. Now that RDD needs pref handling, it
needs its own process selector to avoid GPU inheriting pref
handling.
Differential Revision: https://phabricator.services.mozilla.com/D26566
--HG--
extra : moz-landing-system : lando
Michael Froman
Kris Maglione
arthur.iakab