enh: Add usage of DEFINE_validator to test project
enh: Add usage of DEFINE_validator to test project

n054/gflags,fuchsia-mirror/third_party-gflags,schuhschuh/gflags,n054/gflags,fuchsia-mirror/third_party-gflags,n054/gflags,gflags/gflags,fuchsia-mirror/third_party-gflags,schuhschuh/gflags,schuhschuh/gflags,fuchsia-mirror/third_party-gflags,gflags/gflags,schuhschuh/gflags,gflags/gflags,gflags/gflags,n054/gflags