This allows us to remove the hack where we store the current GL
client version in the Renderer.

BUG=angle:789

Change-Id: I6526f11eaa922325a9a41df0df48b2152e022e26
Reviewed-on: https://chromium-review.googlesource.com/227713Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>