message: Add tf.estimator as a valid v1 api prefix in testAllAPIV1 check in
  tf_upgrade_v2_test.py.
diff: @@ -198,6 +198,7 @@ class TestUpgrade(test_util.TensorFlowTestCase):
  _, _, _, text = self._upgrade("tf." + name)
  if (text and
  not text.startswith("tf.compat.v1") and
  + not text.startswith("tf.estimator") and
  text not in v1_symbols):
  self.assertFalse(
  True, "Symbol %s generated from %s not in v1 API" % (
  