R=clemensh@chromium.org

Bug: 
Change-Id: I0c92aa07e10dcd1e9d9fd34dcaf23885076721b0
Reviewed-on: https://chromium-review.googlesource.com/735724
Commit-Queue: Ben Titzer <titzer@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48922}