checks the number of cards in the Corporation's HQ when it resolve, not when it triggers. If another ability, like from , causes the Corporation to have cards in HQ equal to his/her maximum hand size between the time Vigil triggers and resolves, then Vigil draws the Runner a card.
Vigil+Woman in the RD. Runner chooses to resolve WitRD 1st, corp draws to equal max hand size. Does Vigil then let you draw?