Review requests and groups can be starred, and the star status can be

shown in the datagrids and the review request page.
The star status of an individual object would be looked up via a

database call, wrapped in a method on Profile. An optimization was in

place to avoid this lookup if memcached state told us that the user

didn't have any starred objects. If we wanted to look up the same object

more than once, we'd have more than one database query.
The dashboard worked differently, and in a somewhat invasive way. The

column would pre-fetch the IDs of any displayed rows that were starred,

and then bolt those onto the review request or group as an attribute to

aid caching of the state and rendering of the star indicator.
The dashboard's caching attempt wasn't applicable to general lookup and

rendering, and in practice this meant that we tended to look up the

star status more than once on the review request page.
We now go about this differently.
Profile now maintains a local star_cache attribute, which keys

(model_type, pk) to a boolean indicating if an object is cached. When

we star, unstar, or look up the star state for an object via Profile,

we update this cache, speeding up subsequent lookups. This cuts down on

lookups on the review request page.
The star columns on datagrids are now much more simple and less hacky.

They populate star_cache during the queryset augmentation phase, and

then rendering just renders as normal.
The render_star utility just now needs to call the Profile methods

for checking if the object is starred, and render it appropriately. All

the bolted-on cache attribute checks are gone, and it benefits from

Profile-stored caches.
With Profile managing all lookups, this opens the door for optimizing

things further down the line, if needed. Only Profile needs to

interface with the database, and it owns the cache. There are no

immediate plans for optimizing further, but if we need to, we'll have

one place to do that.

Unit tests pass.
Tested starring and unstarring on the dashboard and group datagrids.

Verified that the state was recorded and loaded correctly on page

load and on the other pages.