message: Qualify references to std::string.
diff: @@ -145,7 +145,7 @@ class FlatBufferModel {
  // lower-bound; ops in the graph may not have an associated runtime version,
  // in which case the actual required runtime might be greater than the
  // reported minimum.
  - string GetMinimumRuntime() const;
  + std::string GetMinimumRuntime() const;
  /// Returns true if the model identifier is correct (otherwise false and
  /// reports an error).
  