User can pass -x=g130, ..., -x=g450 to get output in specific GLSL version. Passing -x=g selects GLSL compatiblity profile. BUG=angleproject:1085 Change-Id: Ia680e219eacb0e8a53b711ae277ecebf069dfdc7 Reviewed-on: https://chromium-review.googlesource.com/287220Reviewed-by: Zhenyao Mo <zmo@chromium.org> Tested-by: Kimmo Kinnunen <kkinnunen@nvidia.com> Commit-Queue: Kimmo Kinnunen <kkinnunen@nvidia.com> Reviewed-by: Jamie Madill <jmadill@chromium.org>
