message: Add string conversion necessary for google import.
diff: @@ -437,9 +437,13 @@ void JsonTranscoderFilter::buildResponseFromHttpBodyOutput(Http::HeaderMap& resp
  Buffer::ZeroCopyInputStreamImpl stream(std::move(frame.data_));
  http_body.ParseFromZeroCopyStream(&stream);
  const auto& body = http_body.data();
  - data.add(body);
  +
  + // TODO(mrice32): This string conversion is currently required because body has a different
  + // type within Google. Remove when the string types merge.
  + data.add(ProtobufTypes::String(body));
  +
  response_headers.insertContentType().value(http_body.content_type());
  - response_headers.insertContentLength().value(body.length());
  + response_headers.insertContentLength().value(body.size());
  return;
  }
  }
  