Mark uniform samplers in an array unused per element https://bugs.webkit.org/show_bug.cgi?id=215630 Fix an issue with the OpenGL backend where entire arrays of uniforms would be marked as unused if a single element was reported as unused by the driver. Bug: angleproject:5006 Change-Id: I9bbb75a5f113472393e8d9f1fb60a7865aa9529a Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2486540 Reviewed-by: Tim Van Patten <timvp@google.com> Reviewed-by: Geoff Lang <geofflang@chromium.org> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: James Darpinian <jdarpinian@chromium.org>