For serializer changes, see goo.gl/Kh2eop

Previous version: https://chromium-review.googlesource.com/955593

BUG=v8:7308

Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: I14c92874d04545eb6d04590bedb21dc402326401
Reviewed-on: https://chromium-review.googlesource.com/968245Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52027}