message: Update sequence_feature_column_test to not rely on Keras.
diff: @@ -24,6 +24,7 @@ from absl.testing import parameterized
  import numpy as np
  from tensorflow.python.client import session
  +from tensorflow.python.feature_column import feature_column_lib as fc_lib
  from tensorflow.python.feature_column import feature_column_v2 as fc
  from tensorflow.python.feature_column import sequence_feature_column as sfc
  from tensorflow.python.feature_column import serialization
  @@ -31,7 +32,6 @@ from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import sparse_tensor
  from tensorflow.python.framework import test_util
  -from tensorflow.python.keras.engine.base_layer import Layer
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import lookup_ops
  from tensorflow.python.ops import math_ops
  @@ -132,7 +132,8 @@ def _get_sequence_dense_tensor(column, features):
  def _get_sequence_dense_tensor_state(column, features):
  - state_manager = fc._StateManagerImpl(Layer(), trainable=True)
  + state_manager = fc._StateManagerImpl(
  + fc_lib.DenseFeatures(column), trainable=True)
  column.create_state(state_manager)
  dense_tensor, lengths = column.get_sequence_dense_tensor(
  fc.FeatureTransformationCache(features), state_manager)
  