tree bd699268de5e0c0e3544b556579663e5247fbc20
parent 454c087be64de626ce3a3ceac6f2aacef85e59ea
author Colin Cross <ccross@android.com> 1550608725 -0800
committer Colin Cross <ccross@android.com> 1550609114 -0800

Allow Singletons to export Make variables

Register any Singletons that implement a MakeVars method as
MakeVarsProviders, and convert the hiddenapi singleton to
use it.

Test: m checkbuild
Change-Id: I6a2044ad34ef46a8b267762ddfeb51aa01d7734d