Fix compilation error on 32-bit systems a99ed554ca606 introduced explicit template instantiations that tunred out to be the same on 32-bit CPUs because GLenum and size_t are the same type. BUG=angleproject:2165 Change-Id: I85fafeff1996cb457f2b718e177944fc6aca50bf Reviewed-on: https://chromium-review.googlesource.com/699839 Commit-Queue: Corentin Wallez <cwallez@chromium.org> Reviewed-by: Corentin Wallez <cwallez@chromium.org>