This patch adds the entry point and related validation for FramebufferTextureEXT defined in OpenGL ES 3.1 extension EXT_geometry_shader. BUG=angleproject:1941 TEST=angle_end2end_tests Change-Id: Id6804e0b3971f52273562ce1a325d8377926a558 Reviewed-on: https://chromium-review.googlesource.com/1069842 Commit-Queue: Corentin Wallez <cwallez@chromium.org> Reviewed-by: Corentin Wallez <cwallez@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org>
