Refactor HLSL texture coordinate output to prepare for wrap modes Wrap modes for integer textures need to be implemented in shaders in HLSL. This requires more complex transformations on the texture coordinates, so store the texture coordinate code for each texture coordinate in a string variable. BUG=angleproject:1244 TEST=dEQP-GLES3.functional.shaders.texture_functions.* (no regression), dEQP-GLES3.functional.texture.units.* (no regression) Change-Id: Iadd9617a7f906aa1d56dabfba6639f932152e6f1 Reviewed-on: https://chromium-review.googlesource.com/336637 Reviewed-by: Corentin Wallez <cwallez@chromium.org> Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>