Move GetUniform size validation to top layer. BUG=angle:571 Change-Id: Ie7064cf85f6a125ccd6cdf1bff89443520e2a06d Reviewed-on: https://chromium-review.googlesource.com/212932 Tested-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org>