message: Make ControlFlowContext.AddInnerOp recursively propagate the inner op to the enclosing context by default.
diff: @@ -1496,7 +1496,8 @@ class ControlFlowContext(object):
  def AddInnerOp(self, op):
  """Notifies a scope about an operator added to an inner scope."""
  - pass
  + if self._outer_context:
  + self._outer_context.AddInnerOp(op)
  def GetControlPivot(self):
  """Returns the pivot node for this context, or None."""
  