Revert "Remove invariant qualifier for input in fragment shader" This reverts commit d842a6b2014447db0676c8a3f5a5e9ae4ce67d9a. Because of WebglConformance_conformance_glsl_bugs_invariant_does_not_leak_across_shaders failure BUG=chromium:659326 Change-Id: I0602e24f3d34ccf852cda865f673c5c7634f82a6 Reviewed-on: https://chromium-review.googlesource.com/403230 Reviewed-by: Yuly Novikov <ynovikov@chromium.org> Commit-Queue: Yuly Novikov <ynovikov@chromium.org>