message: [tf.data] Remove unused headers from dataset.h.
  This change is part of a clean-up that will reduce the dependencies of
  the C++ `tensorflow::Dataset` framework, and move towards the
  possibility of building custom datasets as external plugins.
diff: @@ -17,22 +17,17 @@ limitations under the License.
  #include <memory>
  -#include "tensorflow/core/common_runtime/graph_runner.h"
  #include "tensorflow/core/framework/attr_value.pb.h"
  #include "tensorflow/core/framework/attr_value_util.h"
  #include "tensorflow/core/framework/graph.pb.h"
  +#include "tensorflow/core/framework/op_kernel.h"
  #include "tensorflow/core/framework/register_types.h"
  -#include "tensorflow/core/framework/resource_mgr.h"
  #include "tensorflow/core/framework/variant_encode_decode.h"
  #include "tensorflow/core/framework/variant_tensor_data.h"
  -#include "tensorflow/core/graph/graph.h"
  -#include "tensorflow/core/graph/graph_constructor.h"
  #include "tensorflow/core/graph/graph_def_builder.h"
  #include "tensorflow/core/lib/strings/str_util.h"
  #include "tensorflow/core/lib/strings/strcat.h"
  #include "tensorflow/core/platform/tracing.h"
  -#include "tensorflow/core/util/tensor_bundle/naming.h"
  -#include "tensorflow/core/util/tensor_bundle/tensor_bundle.h"
  // Polymorphic datasets should support all primitive TensorFlow
  // types. Use this macro to expand `m(T)` once for each primitive type
  