Improving performance under breeze icons

[Aleix Pol]

Hi,
As assessed lately, one penalty we have when starting an application
is the icons look-up. It's not really Breeze's fault, the intersection
of the standard we're using and how we're using it makes the situation
slightly complex, hence simplifying it would improve the situation
already.

To get some context, the problem is that whenever we request an icon,
what we do is go through all the provided directories hoping we'll
find it.

Now I'm mentioning breeze because on one hand, it's really awesome how
we're using scalable icons directly but on the other hand we could
look into leveraging it better. Here's some ideas, I'd especially like
the icon designers' opinions so we can find the best situation.

* There's some sizes that we can probably trim right away. Are icons
in the 12 and 16 directory substantially different? Or 22 and 24? I've
checked and pruning these would get us about 5% of failed accesses
back.

* Furthermore, I see there's some icons that aren't on every size (for
example, vcs-added is only in 16 but not in 8 or 22). All in all,
feels like it could be specifying broader categories, especially
considering the scalable nature, such as emblems/small, emblems/big.

* Last, slightly unrelated, there's a risk when the icon differs
greatly (e.g. system-help) from a size to another we'll end up with
unpredictable UI's, maybe it would be possible to rename them to
reflect this.

Do you think there's any possibility we could improve there?

Thanks a lot!
Aleix