GitLab

Spec side change: https://github.com/WICG/webpackage/pull/261

Bug: 803774
Change-Id: I0d0aa289b6f991b3cb09b2f53f6b1fbf752d2bbd
Reviewed-on: https://chromium-review.googlesource.com/1142846Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Commit-Queue: Kunihiko Sakamoto <ksakamoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#576371}