Update code to use gl::Version in as many places as possible to ease ES 3.1
support.

BUG=angleproject:1588

Change-Id: I3490b53a81027cf849dac551a9cc66ce04506144
Reviewed-on: https://chromium-review.googlesource.com/404946Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>