Not in this instance, as the court case wasn't in the US, but in London.
In the UK the Crown Prosecution Service decides whether to prosecute, and that involves 'any views expressed by the victim' [1]. If the victim has withdrawn their complaint, then the CPS will decide whether prosecuting is in 'the public interest'.
It might be more accurate to say that the DA has the final say, but the victim often influences the DA's decision. This is particularly true with a victim like Facebook -- remember that the DA often holds an elected position.
