code: public boolean deleteRoleForUserInDomain(String user, String role, String domain) {
          return removeGroupingPolicy(user, role, domain);
      }
docs: deleteRoleForUserInDomain deletes a role for a user inside a domain.
  Returns false if the user does not have the role (aka not affected).
  
  @param user the user.
  @param role the role.
  @param domain the domain.
  @return succeeds or not.