This CL is adapted from work by matavenrath@nvidia.com. It does the
following small optimizations:

* inlines a bunch of accessors.
* reorders checks to hit the cache more often

Also some small style updates.

Bug: angleproject:1671
Change-Id: I8f21318e6644dcfe1f99c98f7f377742fcad78d3
Reviewed-on: https://chromium-review.googlesource.com/1054367
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>