Pass Context to setLabel. This is useful for triggering a dirty state notification for Textures. It will lead to improvements for program and texture dirty bits. Bug: angleproject:2966 Change-Id: Iaba625da8a970a558f7d158bfa2f09c964f6761a Reviewed-on: https://chromium-review.googlesource.com/c/1347669 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Reviewed-by: Yuly Novikov <ynovikov@chromium.org>