Remove gl::ErrorOrResult.
Remove gl::ErrorOrResult.

Bug: angleproject:2491
Change-Id: Ief728b9c50ee2e1925a9b286c52c8ccda6b14fd2
Reviewed-on: https://chromium-review.googlesource.com/c/1255646
Commit-Queue: Jamie Madill <7e492b4f1c8458024932de3ba475cbf015424c30@chromium.org>
Reviewed-by: Yuly Novikov <36f5580f63d0a3eacc17e89a61d11e2f646630d2@google.com>
Reviewed-by: Frank Henigman <4f3ccfa167f952ff7263448ff4377acff6a23e5c@chromium.org>

ppy/angle,ppy/angle,ppy/angle,ppy/angle