Hi there. I'm glad your dogs are getting along today! =)
This is actually very common, if it is what I think it is. Chloe is maturing and wants to establish dominance over Armani. That's usually when I see it. What I do is either let them deal with it themselves, like someone said, under very close supervision. It should end relatively quickly. If one dog starts squealing or screaming, or if one dog is on its back and the other isn't stopping, then I step in.
Otherwise, it's a lot of watching them and constantly praising them when they're playing well together and correcting the instigator when she starts attacking. I wouldn't separate them though. Correct until she stops, and then leave her. If she starts right away again, correct again. If she behaves after the correction, praise. It helps them learn which exact situations are desirable.