R=alph@chromium.org

Bug: 
Change-Id: Ie9088cd189fcf3af08b06f3021ff4ff1641b7791
Reviewed-on: https://chromium-review.googlesource.com/601928
Commit-Queue: Ben Titzer <titzer@chromium.org>
Reviewed-by: Alexei Filippov <alph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47373}