Add supervised learning flags, as well as wide-deep model type.

def define_wide_deep_flags():
  """Add supervised learning flags, as well as wide-deep model type."""
  flags_core.define_base()
  flags_core.define_benchmark()
  flags_core.define_performance(
      num_parallel_calls=False, inter_op=True, intra_op=True,
      synthetic_data=False, max_train_steps=False, dtype=False,
      all_reduce_alg=False)

  flags.adopt_module_key_flags(flags_core)

  flags.DEFINE_enum(
      name="model_type", short_name="mt", default="wide_deep",
      enum_values=['wide', 'deep', 'wide_deep'],
      help="Select model topology.")
  flags.DEFINE_boolean(
      name="download_if_missing", default=True, help=flags_core.help_wrap(
          "Download data to data_dir if it is not already present."))