Hide 'google' namespace, which protobuf in grpc in firestore uses.
Hide 'google' namespace, which protobuf in grpc in firestore uses.

firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk