R=petermarshall@chromium.org

Bug: chromium:617892
Change-Id: I4077ae567297d18edd6c6748f9f64bbdafb34896
Reviewed-on: https://chromium-review.googlesource.com/616561
Commit-Queue: Yang Guo <yangguo@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47368}