message: Remove hardcoded discovery document now that the TPU alpha API definitions are public (https://www.googleapis.com/discovery/v1/apis/tpu/v1alpha1/rest).
diff: @@ -80,13 +80,9 @@ class TPUClusterResolver(ClusterResolver):
  raise ImportError('googleapiclient must be installed before using the '
  'TPU cluster resolver')
  - # TODO(b/67375680): Remove custom URL once TPU APIs are finalized
  self._service = discovery.build(
  - 'tpu',
  - 'v1',
  - credentials=self._credentials,
  - discoveryServiceUrl='https://storage.googleapis.com'
  - '/tpu-api-definition/v1alpha1.json')
  + 'tpu', 'v1alpha1',
  + credentials=self._credentials)
  else:
  self._service = service
  