message: Fix incorrect usage of keras code in tf.
  TF core shouldn't have any deps back to keras.
diff: @@ -30,7 +30,6 @@ from tensorflow.python.eager import def_function
  from tensorflow.python.eager import test
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import tensor_shape
  -from tensorflow.python.keras.saving.saved_model import json_utils
  from tensorflow.python.layers import core as non_keras_core
  from tensorflow.python.module import module
  from tensorflow.python.ops import array_ops
  @@ -40,6 +39,7 @@ from tensorflow.python.training.tracking import data_structures
  from tensorflow.python.training.tracking import tracking
  from tensorflow.python.training.tracking import util
  from tensorflow.python.util import nest
  +from tensorflow.python.util import serialization
  class ListTests(test.TestCase):
  @@ -47,7 +47,7 @@ class ListTests(test.TestCase):
  def testJSONSerialization(self):
  obj = tracking.AutoTrackable()
  obj.l = [1]
  - json.dumps(obj.l, default=json_utils.get_json_type)
  + json.dumps(obj.l, default=serialization.get_json_type)
  def testNotTrackable(self):
  class NotTrackable(object):
  @@ -337,7 +337,7 @@ class MappingTests(test.TestCase):
  def testJSONSerialization(self):
  obj = tracking.AutoTrackable()
  obj.d = {"a": 2}
  - json.dumps(obj.d, default=json_utils.get_json_type)
  + json.dumps(obj.d, default=serialization.get_json_type)
  def testNoOverwrite(self):
  mapping = data_structures.Mapping()
  @@ -519,7 +519,7 @@ class TupleTests(test.TestCase, parameterized.TestCase):
  def testJSONSerialization(self):
  obj = tracking.AutoTrackable()
  obj.l = (1,)
  - json.dumps(obj.l, default=json_utils.get_json_type)
  + json.dumps(obj.l, default=serialization.get_json_type)
  def testNonLayerVariables(self):
  v = resource_variable_ops.ResourceVariable([1.])
  