message: Update auto_shard.cc to apply the rewrite even in the 1 worker case for data-based sharding for more consistency (namely: data sharding -> LegacyRebatch, file / no sharding -> Rebatch).
diff: @@ -561,7 +561,8 @@ Status ShardByData(const NodeDef& sink_node, int64 num_workers, int64 index,
  Status OptimizeGraph(const GrapplerItem& item, int64 num_workers, int64 index,
  AutoShardPolicy policy, int64 num_replicas,
  GraphDef* output) {
  - if (policy == AutoShardPolicy::OFF || (num_workers == 1 && index == 0)) {
  + if (policy == AutoShardPolicy::OFF ||
  + (policy == AutoShardPolicy::FILE && num_workers == 1 && index == 0)) {
  return Status::OK();
  }
  