Art needs a custom module type in order to perform complicated
build logic like depending on environment variables and varying
cflags based on cpu variant. Export enough of the types and
functions from cc for art_cc_library to inherit from cc_library.
While I'm touching every line, also rename the New* methods
to *Factory.
Change-Id: I7123aa47019c4ced7a1ab57c394225bc7844b5ea