<Real Talk>
Quite frankly, very few people run OSPF between their Routers and Aruba Controllers They normally just bridge user traffic from controllers to layer3 switches and whatever protocols the layer3 switches are running, bridging the traffic to them leverages that routing or redundancy.
One practical situation where OSPF is run between controllers and routing infrastructure is if you have RAPs connecting to controllers in disparate datacenters. The primary controller would advertise reachability for a subnet that clients on a RAP would need to be on. When there is failover, either a lower priority or a floating static route would satisfy RAPs failing over from one controller to another. Those clients would be able to maintain their same ip addresses and reachability for that specific client subnet would be shifted to the new controller.
Outside of that there are some corner cases where OSPF would provide reachability for different paths to the internet, BUT, that could easily be provided by a single router or dual routers that are already providing this reachability to other devices.
</Real Talk>
Maybe somebody can chime in on the utility of the diagram above in a way that is useful for you. I just want to save you some time.