message: Trivial fixes in the file.
  Fixed some triva issues.
diff: @@ -1097,7 +1097,7 @@ void FixOperatorOrdering(Model* model) {
  std::unordered_map<string, string> reason_why_leftover;
  while (true) {
  bool inserted_something = false;
  - for (auto i : remaining) {
  + for (const auto& i : remaining) {
  bool can_insert = true;
  auto& op = old_operators[i];
  CHECK(op);
  @@ -1167,7 +1167,7 @@ void FixOperatorOrdering(Model* model) {
  }
  bad_inputs_already_traced.insert(bad_input);
  bad_op = nullptr;
  - for (auto i : remaining) {
  + for (const auto& i : remaining) {
  const Operator* op = old_operators[i].get();
  for (const string& output : op->outputs) {
  if (bad_input == output) {
  @@ -1640,7 +1640,7 @@ void ResolveModelFlags(const ModelFlags& model_flags, Model* model) {
  if (input_array_proto.has_shape()) {
  auto& input_array_dims = *input_array.mutable_shape()->mutable_dims();
  CheckValidShapeDimensions(input_array_proto.shape().dims());
  - for (auto dim : input_array_proto.shape().dims()) {
  + for (const auto& dim : input_array_proto.shape().dims()) {
  input_array_dims.push_back(dim);
  }
  }
  