For serializer changes, see goo.gl/Kh2eop

BUG=v8:7308

Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: I2b790413a4c0d8c8cc0c07ba7b901c965d64eb11
Reviewed-on: https://chromium-review.googlesource.com/955593
Commit-Queue: Marja Hölttä <marja@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51895}