This patch implements GL_REFERENCED_BY_GEOMETRY_SHADER as a valid property of program interfaces. BUG=angleproject:1941 TEST=angle_end2end_tests dEQP-GLES31.functional.geometry_shading.query.referenced_by_geometry_shader Change-Id: Id9659313d371dbfc7d00bf9d816df4449fbf29ec Reviewed-on: https://chromium-review.googlesource.com/1025281Reviewed-by: Jiajia Qin <jiajia.qin@intel.com> Reviewed-by: Geoff Lang <geofflang@chromium.org> Reviewed-by: Corentin Wallez <cwallez@chromium.org> Commit-Queue: Jiawei Shao <jiawei.shao@intel.com>
