The building in question is 109 Men's, a men's department store in Shibuya , one of the busiest parts of Tokyo and usually the place used in "We're in Tokyo" establishing shots on film and TV. Tokyo's equivalent of Times Square or Piccadilly Circus basically.
Here's a photo. Note the massive screen.
I'd be extremely surprised if it was a gig. Shibuya crossing isn't exactly the quietest place in the world. They'd need a truly powerful sound system to play properly. The screen does have sound, if I recollect correctly, but it's not exactly high quality audio. It's used to blast out advertising messages, not play intricate and detailed music to the world for the first time.
I'd imagine there will be something interesting on the screen. All the other buildings around there also have massive screens, so possibly multiple screens will be used. Very exciting. Wish I was in Tokyo to see it.