It's really hard to say. It clearly was a foul, and a foul in the box should always be a penalty, but referees everywhere have taking up this nasty habit of judging some fouls as not bad enough to justify a penalty, which is clearly not within the rules, so some players getting fouled have taken up the habit of flopping like they want an academy award when they think they just got hit in the box.
That results in these situations, Robben clearly got fouled, yet if he hadn't flopped, maybe there wouldn't have been a penalty, when there should have been. Especially after the referee didn't call a penalty on RVP earlier, I can understand why the players do this.