Def Jam. They'll count them where it matters to them: in their accounting books. I doubt they care if those sales are printed on a Billboard magazine or article (which no one reads).
NO! Def Jam and every other label goes by shipments. Even if Google doesn't sell 1 single Rihanna album, Def Jam will still 'count' the shipments in their accounting books. So again this won't have any bearing on Rihanna's official sales because Billboard and Soundscans won't count the sells.
It shouldn't be bad for Def Jam. They're still getting the money. That's all labels really need to worry about. Chart positions are child's play to them, and serve no other purpose than being trophies for stans.
It's good for fans, Rihanna, AND DefJam, but is only really bad for crazy chart-crazed fans. DJ doesn't take a cut from how much money it gets per album, it's all Google.