R=titzer@chromium.org

Change-Id: I637cbafc99caf1ada1d92d41f7796cf5551bc532
Reviewed-on: https://chromium-review.googlesource.com/588895
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47667}