Fix missing bracket in translator source. Broken in ed14b79dc8e9ec4f4a831bb5213ab67ef01af196. BUG=angle:628 Change-Id: Ia6b92dd13362bb51f0aa17a14278039d568f5434 Reviewed-on: https://chromium-review.googlesource.com/202182 Tested-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Nicolas Capens <nicolascapens@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org>