Pass bit mask to ContextImpl::syncState. This can be used to mask out inappropriate local dirty bits. Bug: angleproject:2763 Change-Id: Ie46e464df0dc719c963ff9f7066d42eb5a028262 Reviewed-on: https://chromium-review.googlesource.com/c/1264062 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Yuly Novikov <ynovikov@google.com>