The patch adds all shader built-in constants. BUG=angleproject:1442 TEST=angle_unittests TEST=angle_end2end_tests Change-Id: I81cae479d6506a8faa2dce023d5fcc2c1291d521 Reviewed-on: https://chromium-review.googlesource.com/364460Reviewed-by: Corentin Wallez <cwallez@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
