message: Override "map_resources" in AggregatingVariable.
diff: @@ -166,6 +166,14 @@ class AggregatingVariable(variables_lib.Variable, core.Tensor):
  def _gather_saveables_for_checkpoint(self):
  return {trackable.VARIABLE_VALUE_KEY: self._v}
  + def _map_resources(self):
  + """For implementing `Trackable`."""
  + # By delegating this method to the wrapped variable, SavedModel with
  + # AggregatingVariable are identical to SavedModel with normal variables.
  + obj_map, resource_map = self._v._map_resources() # pylint:disable=protected-access
  + obj_map[self] = obj_map[self._v]
  + return obj_map, resource_map
  +
  # pylint: disable=multiple-statements
  def __add__(self, o):
  return self._v + o
  