No functional changes - except protobuffer is mandatory and not optional now. Former-commit-id: 1e6347e708707cc388cdedb8d0352a9f017030b8
Former-commit-id: 7f0971ccda221933da4be836628532e7cfc7c085
Former-commit-id: 46176e53d1acf39f9bd0c0ecbb8e5fb5ab4d45be