Good method to rig an eye for Unity Game Engine

Can anyone give me any advice for rigging my character to blink for export to Unity game engine. I had a try with the Blender/Unity Shape Key add-on but that exporter didn’t show up for me. I’m thinking bones would be a better way to go, but the original animation rig was based on the David Ward Alien Tutorial and had loads of bones and constraints. Is there a way to get the eye to close nicely without resorting to masses of bones etc?

In this model the white part of the eye is not a sphere segment inside the head, but just textured head mesh. The Pupil is a separate piece of mesh, currently. We’re exporting via .fbx to unity, to hopefully try out mecanim.
Thanks for reading,