No functional changes - except protobuffer is mandatory and not optional now. Former-commit-id: 1e6347e708707cc388cdedb8d0352a9f017030b8
Former-commit-id: ba15d222339736e5281e667270ddb37b50d1319f
Former-commit-id: 26cab1b85b00406240689ad9c1018f0307028fe4