Pass GL context data into shader creation.

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/227713
Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Remove the unused Renderer client version methods.

Previous patches enable us to get rid of this workaround. We should
in subsequent patches also try to clean up code that uses the
internal Renderer-only version of the context caps.

BUG=angle:789

Change-Id: Ic054090303cdc3f7ee8e45e4577c157559955472
Reviewed-on: https://chromium-review.googlesource.com/227714
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Brandon Jones <bajones@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>
Remove redundant rx:: scoping prefixes.

In many places we can get rid of this scoping operator.

BUG=angle:789

Change-Id: If6c40c435a97473d2fd9d6f1fb5a2c709393eb00
Reviewed-on: https://chromium-review.googlesource.com/225566
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Brandon Jones <bajones@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>