This field is also no longer used in some factory methods, which means
many callers need to get updated as well. One side effect is to
consolidate many of the GenericFactory#create methods. This in turn
means that the remote peer provider is never null; previously the code
was treating a null Provider and a Provider that returns null
identically, so this should have no behavior change.
Change-Id: I107fcfbd1a1d8daa15ee3afc02c8e7e709ffb3ea
0f8b4118b7