Is an agreement for payment of attorney fees enforceable as an item of special damages?

"An agreement for payment of attorney's fees of the prevailing party is enforceable as an item of special damages, and a contract may permit recovery of attorney's fees in the event of suit to enforce the contract. [Citations.]" (Wiener v. Van Winkle (1969) 273 Cal.App.2d 774, 784, 78 Cal.Rptr. 761, 767.) "The purpose of upholding an attorney's fees provision in a promissory note is to allow a plaintiff to recover the full amount due him without such amount being diminished by attorney's fees." (Id., at p. 788, 78 Cal.Rptr. at p. 770.)