This is a very confusing issue. I suppose the best thing to do is to ask Ms. Harris how she would like to be identified. Although I wouldn't ask anyone "what are you." I may ask, as a journalist, how he/she would like to be identified in the article.
I know two sisters, Asian mother and Af Am father, who differ in how they would like to be identified. One just says, "I'm black" (and is interested in Our Fine Sorority, BTW) and the other is adamant about not leaving out her Asian heritage if you chose to label her at all.
Have you ever heard of a campus student group called HAPA? They are a group of people who are of partly Asian descent; all of them are Asian and (something else). It seems that there are many of these types of groups cropping up. Many people whose looks don't define their race seem to like to associate with groups where their identity is defined by the group so that they can avoid questions, I guess.
Anyway, very confusing. I guess the "one drop" rule doesn't apply any more, for many, many, many reasons. Things are changing and I'm trying to understand but it seems like the "Black" population is getting smaller and smaller as people of racially mixed parentage chose not to identify as Black (probably in part because young black people who do identify as black don't accept when people who don't look black say they're black). How do we unify and have strenghth in numbers if this is the way the trend is swinging?