Create an Error object to represent GL errors. BUG=angle:520 Change-Id: I1a54e6f308b5b0f310c725a7771af737a77ecd42 Reviewed-on: https://chromium-review.googlesource.com/209619 Reviewed-by: Jamie Madill <jmadill@chromium.org> Tested-by: Geoff Lang <geofflang@chromium.org>