Fix exposing internal shader interface variables Don't expose internal variables in the shader translator interface. This affects the ViewID_OVR varying needed for instanced multiview, which is so far the only variable of this kind. This fixes the translator trying to add initialization for internal variables in initializeOutputVariables. Since they are variables added by ANGLE, they should never need extra initialization. BUG=angleproject:2112 TEST=angle_unittests Change-Id: I93ee2956c8180053806ce450d93f162f78a45d8f Reviewed-on: https://chromium-review.googlesource.com/579050 Reviewed-by: Corentin Wallez <cwallez@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>