message: [tf.data] Remove obsolete StatsAggregator code from IteratorResource.
diff: @@ -207,12 +207,6 @@ class IteratorResource : public ResourceBase {
  return Status::OK();
  }
  -
  - std::shared_ptr<StatsAggregator> stats_aggregator() {
  - tf_shared_lock l(mu_);
  - return stats_aggregator_;
  - }
  -
  string DebugString() override { return "Iterator resource"; }
  const DataTypeVector& output_dtypes() const { return output_dtypes_; }
  @@ -231,7 +225,6 @@ class IteratorResource : public ResourceBase {
  FunctionLibraryRuntime* lib_ = nullptr; // not owned.
  std::shared_ptr<IteratorBase> iterator_;
  mutex mu_;
  - std::shared_ptr<StatsAggregator> stats_aggregator_ GUARDED_BY(mu_);
  std::shared_ptr<const FunctionLibraryDefinition> lib_def_ GUARDED_BY(mu_);
  const DataTypeVector output_dtypes_;
  const std::vector<PartialTensorShape> output_shapes_;
  @@ -944,9 +937,6 @@ class IteratorGetNextOp : public AsyncOpKernel {
  IteratorContext::Params params;
  params.env = ctx->env();
  - params.stats_aggregator_getter = [iterator]() {
  - return iterator->stats_aggregator();
  - };
  params.runner = *(ctx->runner());
  params.function_library = iterator->function_library();
  DeviceBase* device = ctx->function_library()->device();
  @@ -995,9 +985,6 @@ class IteratorGetNextSyncOp : public OpKernel {
  IteratorContext::Params params;
  params.env = ctx->env();
  - params.stats_aggregator_getter = [iterator]() {
  - return iterator->stats_aggregator();
  - };
  params.runner = *(ctx->runner());
  params.function_library = iterator->function_library();
  DeviceBase* device = ctx->function_library()->device();
  