The following revision refers to this bug:
  https://chromium.googlesource.com/v8/v8.git/+/568979f4d891bafec875fab20f608ff9392f4f29

commit 568979f4d891bafec875fab20f608ff9392f4f29
Author: Toon Verwaest <verwaest@chromium.org>
Date: Wed Sep 26 11:17:31 2018

[parser] Fix memory accounting of explicitly cleared zones

Bug:  chromium:889086 
Change-Id: Ie5a6a9e27260545469ea62d35b9571c0524f0f92
Reviewed-on: https://chromium-review.googlesource.com/1245427
Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56235}
[modify] https://crrev.com/568979f4d891bafec875fab20f608ff9392f4f29/src/parsing/parser.cc
[modify] https://crrev.com/568979f4d891bafec875fab20f608ff9392f4f29/src/zone/zone.cc
[modify] https://crrev.com/568979f4d891bafec875fab20f608ff9392f4f29/src/zone/zone.h

The following revision refers to this bug:
  https://chromium.googlesource.com/v8/v8.git/+/400be60c134a08e0739a432346f4612490847567

commit 400be60c134a08e0739a432346f4612490847567
Author: Toon Verwaest <verwaest@chromium.org>
Date: Wed Sep 26 14:17:43 2018

[parser] Allocate preparsed scope members in preparse zone

Before I gave the preparser its own zone this was the case. I somewhat
accidentally dropped it when I used set_zone instead; causing large regressions
for certain types of pages.

Bug:  chromium:889086 
Change-Id: Ib3cf1f926b5c65506c66a97981c4544dccb372aa
Reviewed-on: https://chromium-review.googlesource.com/1245767
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56243}
[modify] https://crrev.com/400be60c134a08e0739a432346f4612490847567/src/ast/scopes.cc
[modify] https://crrev.com/400be60c134a08e0739a432346f4612490847567/src/parsing/parser-base.h
[modify] https://crrev.com/400be60c134a08e0739a432346f4612490847567/src/parsing/parser.cc
[modify] https://crrev.com/400be60c134a08e0739a432346f4612490847567/src/parsing/parser.h
[modify] https://crrev.com/400be60c134a08e0739a432346f4612490847567/src/parsing/preparser.cc
[modify] https://crrev.com/400be60c134a08e0739a432346f4612490847567/src/parsing/preparser.h