This cleanup prepares us for removing the uniform register info
from the shader translator types.

BUG=angle:466

Change-Id: I86f47970b793135f410a5ef698fc96d44219ee96
Reviewed-on: https://chromium-review.googlesource.com/207253Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>