SurfaceGL had these methods already so they are just moving up the inheritance
hierarchy.  This ends up simplifying some state tracking we had in our surface
implementations.

BUG=angleproject:2464

Change-Id: I480588ca8470d9ef507f95e0c0297fe126b3abfb
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1595434Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>