Merge pull request #15840 from dgquintas/common_nanopb

BUILD

CMakeLists.txt

Makefile

build.yaml

config.m4

config.w32

gRPC-Core.podspec

grpc.gemspec

grpc.gyp

package.xml

...ters/client_channel/lb_policy/grpclb/load_balancer_api.cc

...lters/client_channel/lb_policy/grpclb/load_balancer_api.h

...icy/grpclb/proto/grpc/lb/v1/google/protobuf/duration.pb.c

...icy/grpclb/proto/grpc/lb/v1/google/protobuf/duration.pb.h

...cy/grpclb/proto/grpc/lb/v1/google/protobuf/timestamp.pb.c

...cy/grpclb/proto/grpc/lb/v1/google/protobuf/timestamp.pb.h

...nnel/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c

...nnel/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h

src/core/tsi/alts/handshaker/altscontext.pb.c

src/core/tsi/alts/handshaker/altscontext.pb.h