Unfortunately, the Open Gaming license doesn't allow you to adapt the D20 system into a computer game. So, they would have to develop a different rule set. As amusing as it would be to see Tim Cain develop a turn-based D&D 3.75 cRPG to school the Sword Coast Legends guys, they'll have to go a different direction on whatever cRPG they decide to make.
Unless they've got some kind of contingency I know nothing about.
Actually some people think that's not correct.
There was discussion in this thread about it already.
http://forums.obsidian.net/topic/66652-pathfinder-crpg-by-obsidian/?p=14766Well39
Well, all I can say is that if Obsidian intends on making a Pathfinder cRPG using d20 rules they had best announce development now so they can get the lawsuit out of the way sometime by 2020. At least by that point we could have had an Eternity trilogy and nobody will question them if they take a similar direction with this license.
KickStart Paizo/Obsidian's legal fees so that they can make a d20 cRPG.
It's possible they can use the Golarion world (aka Forgotten Realms for adults) without needing the d20 license. Pillars of Eternity (or even Arcanum before PoE) proves they can make a game without aping any d20, but still keeping to the class based structure of basic DnD. Wizards/Hasbro doesn't own all rulesets.
The pros of the Pathfinder license is it already has a HUGE mythos associated with it in Golarion. It might not be Forgotten Realms, but personally I think it has more scope, creativity and believability than FR.