This refactor uses a generator to produce static arrays instead of
using a bunch of std::map inserting statements. It speeds up shader
translation because every shader compile would create and tear down
this table.

Currently it is implemented as a flat array, but in the future we
could use compile-time hashing to implement faster lookup.

BUG=chromium:697758

Change-Id: I689f7de4d9b2c8c76095bb313f4c040116fc61d2
Reviewed-on: https://chromium-review.googlesource.com/521226
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Olli Etuaho <oetuaho@nvidia.com>