If you read the article it's a very interesting theory.
Could Booster Gold Finally Unite DC's TV and Film Universes?
http://comicbook.com/2015/09/18/could-booster-gold-finally-unite-dcs-tv-and-film-universes-/
And, yes, giving Zack Snyder control of Man of Steel and Greg Berlanti the chance to shape Supergirl has created a universe where the two are clearly not sharing real estate, even if they share a common point of origin (Krypton, of course).
But...what if this is it? What if this is the moment where the DC Extended Universe becomes a little more cohesive?
Why, of all characters, would Booster Gold be the one to do it?
Well, we have some thoughts on that.
First of all, the movie I'm choosing to call Blue and Gold until somebody tells me different is set in the same shared universe as the Justice League films, at least as far as anyone can tell. That said, it's to be produced and directed by Greg Berlanti, best known for producing Supergirl, The Flash, Arrow and Legends of Tomorrow.
Berlanti has reportedly been the biggest booster (no pun intended) for Supergirl to share a universe with his other shows, while CBS has thus far been reluctant. He and his cohorts Marc Guggenheim and Andrew Kreisberg have an appreciation for the history of DC Comics that many filmmakers don't necessarily seem to share.
For instance, they're introducing the multiverse this year on The Flash, and they're doing it exactly the way it was done in DC Comics during the Silver Age: with the meeting of Barry Allen and Jay Garrick, The Flashes of Earth-1 and Earth-2.
That same series, of course, teased Barry Allen's death in Crisis on Infinite Earths as far back as the pilot. Following the events of Crisis when it happened in the comics, the DC Multiverse disappeared, replaced by a single universe, until 2005 when Infinite Crisis reworked the fabric of space and time.
...And who discovered the new DC Multiverse? Rip Hunter, star of Berlanti's Legends of Tomorrow, and Booster Gold, Rip's father.
They would serve as Time Masters, the guardians of reality, for a long while after that, with that role ultimately wrapping up in Convergence, which restored a full, infinite multiverse to the DC canon.
Could the same people who faithfully depict (with a margin for error) the birth of DC's mutliverse also be the ones to faithfully depict (with a margin for error) the discovery of same in the films?
A connection between Booster Gold and Rip Hunter, played through Blue and Gold and Legends of Tomorrow, could easily be kept from most or all fo the other characters, excepting perhaps Ezra Miller's cinematic Flash, since Miller has already made remarks about parallel universes.
After all, they discovered the Multiverse in 52 and then for all intents and purposes didn't share that information with anyone until Flashpoint. So it isn't as though just establishing "Yeah, these guys are aware that one another exist out there somewhere in the multiverse" doesn't immediately mean that Booster and Beetle will be spending time making guest appearance on Legends and telling Team Arrow about their meeting with Superman.