TName used to contain just a subset of the information stored in
TSymbol. It makes more sense to use TSymbol directly instead of
converting it to TName.
This also improves type safety a bit by making some functions only
take in TVariable or TFunction instead of the more generic TName.
BUG=angleproject:2267
TEST=angle_unittests
Change-Id: Icb46923c25d33ebbbbc06ddc487da25957dda771
Reviewed-on: https://chromium-review.googlesource.com/829143
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
