The global invariant pragma must not leak across compilations. BUG=chromium:625363 TEST=conformance/glsl/bugs/global-invariant-does-not-leak-across-shaders.html Change-Id: Ie8d38e44837fc87bb4c94e76e779ad41e8b79957 Reviewed-on: https://chromium-review.googlesource.com/358203 Reviewed-by: Corentin Wallez <cwallez@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Corentin Wallez <cwallez@chromium.org> Commit-Queue: Zhenyao Mo <zmo@chromium.org>