message: [Grappler] Move the output graph in ModelPruner::Optimize().
diff: @@ -622,7 +622,7 @@ Status ModelPruner::Optimize(Cluster* cluster, const GrapplerItem& item,
  }
  }
  - *optimized_graph = graph;
  + *optimized_graph = std::move(graph);
  return Status::OK();
  }
  