The following revision refers to this bug:
  https://chromium.googlesource.com/v8/v8.git/+/9664d017f7e219878d4b1a6c25be6c6f9b1b91bd

commit 9664d017f7e219878d4b1a6c25be6c6f9b1b91bd
Author: jgruber <jgruber@chromium.org>
Date: Wed Nov 08 13:09:07 2017

[snapshot] Flip --lazy-handler-deserialization

Flip this for a day or two to gather perf bot results & stability
issues. Results will be collected in  https://crbug.com/782637 .

TBR=hablich@chromium.org

Bug:  v8:6624 ,  chromium:782637 
Change-Id: I70eb5d6287d4723f935715ef80d9ba129dc282f0
Reviewed-on: https://chromium-review.googlesource.com/758375
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49222}
[modify] https://crrev.com/9664d017f7e219878d4b1a6c25be6c6f9b1b91bd/src/flag-definitions.h

Convenient link to chromiumdash: 

https://chromiumdash-staging.googleplex.com/commit/9664d017f7e219878d4b1a6c25be6c6f9b1b91bd

The following revision refers to this bug:
  https://chromium.googlesource.com/v8/v8.git/+/b0996927fb63f1e2277c8d1cddf4cae2435bdedb

commit b0996927fb63f1e2277c8d1cddf4cae2435bdedb
Author: Jakob Gruber <jgruber@chromium.org>
Date: Fri Nov 10 10:46:33 2017

Revert "[snapshot] Flip --lazy-handler-deserialization"

This reverts commit 9664d017f7e219878d4b1a6c25be6c6f9b1b91bd.

Reason for revert: Planned revert, this is on Canary 3264 and V8
branch 6.4.245.

Original change's description:
> [snapshot] Flip --lazy-handler-deserialization
>
> Flip this for a day or two to gather perf bot results & stability
> issues. Results will be collected in  https://crbug.com/782637 .
>
> TBR=hablich@chromium.org
>
> Bug:  v8:6624 ,  chromium:782637 
> Change-Id: I70eb5d6287d4723f935715ef80d9ba129dc282f0
> Reviewed-on: https://chromium-review.googlesource.com/758375
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Commit-Queue: Jakob Gruber <jgruber@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#49222}

TBR=hablich@chromium.org,jgruber@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug:  v8:6624 ,  chromium:782637 
Change-Id: I2a6ee63f7191d186810d7352ee63b6b664e74157
Reviewed-on: https://chromium-review.googlesource.com/763427
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49290}
[modify] https://crrev.com/b0996927fb63f1e2277c8d1cddf4cae2435bdedb/src/flag-definitions.h

A quick analysis of chromeperf/ alerts (https://chromeperf.appspot.com/group_report?rev=515142):

Memory improvements across the board, all arches, all platforms. Usually at least 250K but often reaching 600K+ for all_processes. e.g.:

https://chromeperf.appspot.com/report?sid=9c8093256c372f4343dec644a057c745085b2f4ef9d4fd695066f25a631f0ded&rev=515186
https://chromeperf.appspot.com/report?sid=c3035e159ec2260ba8630319313e42bca14d50488f054ff37dfc444d70a6cbca&rev=515182
https://chromeperf.appspot.com/report?sid=f40593d9a3eb5b4d11da7bf3d6497779019572c54b0f51b73374fa016583f577&rev=515213
https://chromeperf.appspot.com/report?sid=895bf731b6a8eb32b5070835702388841a02f8a2b7e01372c2f5a94a6f08e86a&rev=515213
https://chromeperf.appspot.com/report?sid=a7c848d40c54176d387af082037f679d0f9eda08576bfdf7acf5962d7e96d8d1&rev=515213

RCS:

Parse-time changes are unrelated.

gc-full-mark-compactor:

This tanks and should be investigated.

https://chromeperf.appspot.com/report?sid=336583d608473394c0dbb0504f1bfd7d65ecc519b0673d0ca1f69a8b61bd5628&rev=515164
https://chromeperf.appspot.com/report?sid=9ebaabd28135acf094fc37a097593c16a4b74ee82f0ee09f6dc791171915f8fc&rev=515524

 Issue 787453  has been merged into this issue.

Issue 787817 has been merged into this issue.

Experiment is over and the flag has been landed. gc-full-mark-compactor regressions from #4 seem to come from a shift in gc timing (thanks ulan for the investigation).