Some countries decided to change the timezone almost the last moment. At least, this has to be in M63 if not M62. 

Mike, can you bump tzdb to 2017c in the Gentoo upstream ? 
 ( https://packages.gentoo.org/packages/sys-libs/timezone-data )

Test:

In JavaScript console, run the 4 lines below (starting with '>') to get the results shown below. Nov 1st, Sudan is switching from UTC+3 to UTC+2
( Africa/Khartoum ), but South Sudan (Africa/Juba) will stay in UTC+3. 


> (new Date(Date.UTC(2017,9, 31, 12))).toLocaleString("en", {'timeZone': 'Africa/Khartoum'})
"10/31/2017, 3:00:00 PM"

> (new Date(Date.UTC(2017,10, 1, 12))).toLocaleString("en", {'timeZone': 'Africa/Khartoum'})
"11/1/2017, 2:00:00 PM"

> (new Date(Date.UTC(2017,9, 31, 12))).toLocaleString("en", {'timeZone': 'Africa/Juba'})
"10/31/2017, 3:00:00 PM"

> (new Date(Date.UTC(2017,10, 1, 12))).toLocaleString("en", {'timeZone': 'Africa/Juba'})
"11/1/2017, 3:00:00 PM"

> Mike, can you bump tzdb to 2017c in the Gentoo upstream ? 
> ( https://packages.gentoo.org/packages/sys-libs/timezone-data )

I filed https://bugs.gentoo.org/636464 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/deps/icu.git/+/4b5a7240d2dfa0cb5627f20a26ceffd67930d134

commit 4b5a7240d2dfa0cb5627f20a26ceffd67930d134
Author: Jungshik Shin <jshin@chromium.org>
Date: Fri Nov 03 21:34:24 2017

Update IANA tzdb to 2017c

Bug:  chromium:778300 
Test: See bug commment 4
Change-Id: I1ae525323cb3354d3936a92e66cff266ebca2fb4
Reviewed-on: https://chromium-review.googlesource.com/738833
Reviewed-by: Mark Mentovai <mark@chromium.org>

[modify] https://crrev.com/4b5a7240d2dfa0cb5627f20a26ceffd67930d134/android/icudtl.dat
[modify] https://crrev.com/4b5a7240d2dfa0cb5627f20a26ceffd67930d134/common/icudtb.dat
[modify] https://crrev.com/4b5a7240d2dfa0cb5627f20a26ceffd67930d134/common/icudtl.dat
[modify] https://crrev.com/4b5a7240d2dfa0cb5627f20a26ceffd67930d134/ios/icudtl.dat
[modify] https://crrev.com/4b5a7240d2dfa0cb5627f20a26ceffd67930d134/source/data/misc/metaZones.txt
[modify] https://crrev.com/4b5a7240d2dfa0cb5627f20a26ceffd67930d134/source/data/misc/windowsZones.txt
[modify] https://crrev.com/4b5a7240d2dfa0cb5627f20a26ceffd67930d134/source/data/misc/zoneinfo64.txt

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/23d0b048bf7e4974eb6870c99a3639015b654b2d

commit 23d0b048bf7e4974eb6870c99a3639015b654b2d
Author: Jungshik Shin <jshin@chromium.org>
Date: Fri Nov 03 23:45:22 2017

Roll ICU to 4b5a7240d2

It has just one change to update IANA tzdb to 2017c
 ( https://chromium-review.googlesource.com/738833 ).

TBR=mark@chromium.org

Bug:  chromium:778300 
Test: See bug commment 4
Change-Id: Ia149560be38653112dc7a650f1d9a2fd8927a722
Reviewed-on: https://chromium-review.googlesource.com/754053
Reviewed-by: Jungshik Shin <jshin@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Commit-Queue: Jungshik Shin <jshin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#513962}
[modify] https://crrev.com/23d0b048bf7e4974eb6870c99a3639015b654b2d/DEPS

 > filed https://bugs.gentoo.org/636464 

Upstream fixed it. I'll update sys-libs/timezone-data per 
https://sites.google.com/a/chromium.org/dev/chromium-os/gentoo-package-upgrade-process .

Upstream used EAPI=6, but our portage is still EAPI=5. Just setting EAPI to 5 with the upstream ebuild does not work because it uses EAPI6-only features (e.g. eapply). 

Mike, should I add a forked version to chromiumos-overlay ?  

Test for CrOS:

After installing timezone-data-2017c on a device,  run the following. The former should be 1 hour ahead of the latter (in Nov 2017). 

$ TZ=Africa/Juba date
$ TZ=Africa/Khartoum date

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/overlays/portage-stable/+/0dc5584c822949a950e54dce5ac705df35faa170

commit 0dc5584c822949a950e54dce5ac705df35faa170
Author: Jungshik Shin <jshin@chromium.org>
Date: Thu Nov 09 03:48:56 2017

Update IANA timezone data to 2017c

Modify the upstream 2017c ebuild slightly to get it
to work with EAPI=5. The only change other than setting
EAPI to 5 is to replace 'eapply' with 'epatch'.

BUG= chromium:778300 
TEST=See bug comment 12

Change-Id: Iecc3898dd059bd7d16f1640ee35ec404072988a0
Reviewed-on: https://chromium-review.googlesource.com/757993
Commit-Ready: Jungshik Shin <jshin@chromium.org>
Tested-by: Jungshik Shin <jshin@chromium.org>
Reviewed-by: Chirantan Ekbote <chirantan@chromium.org>

[modify] https://crrev.com/0dc5584c822949a950e54dce5ac705df35faa170/sys-libs/timezone-data/Manifest
[rename] https://crrev.com/0dc5584c822949a950e54dce5ac705df35faa170/sys-libs/timezone-data/files/timezone-data-2017c-makefile.patch
[rename] https://crrev.com/0dc5584c822949a950e54dce5ac705df35faa170/sys-libs/timezone-data/timezone-data-2017c.ebuild

Merge Request to 63 (baked in canary builds )

1. All platforms: ICU DEPS roll (comment 9). Actual change in comment 8.
2. CrOS: Change in comment 13. 

This is a routine timezone database update. Although there are not many users, some regions have timezone changes that went into effect in late October/early November. 

This bug requires manual review: Less than 18 days to go before AppStore submit on M63
Please contact the milestone owner if you have questions.
Owners: cmasso@(Android), cmasso@(iOS), gkihumba@(ChromeOS), govind@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Approving merge or all non chrome os platforms per comment #14 to M63 branch 3239. Please merge ASAP so we can take it in for this week beta release. Thank you.

gkihumba@ for Chrome OS change approval.

Ok to merge cros

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/overlays/portage-stable/+/f45b5e6f55eea575f579a7462a2441c56573dcb1

commit f45b5e6f55eea575f579a7462a2441c56573dcb1
Author: Jungshik Shin <jshin@chromium.org>
Date: Tue Nov 14 05:48:23 2017

Update IANA timezone data to 2017c

Modify the upstream 2017c ebuild slightly to get it
to work with EAPI=5. The only change other than setting
EAPI to 5 is to replace 'eapply' with 'epatch'.

BUG= chromium:778300 
TEST=See bug comment 12

Change-Id: Iecc3898dd059bd7d16f1640ee35ec404072988a0
Previous-Reviewed-on: https://chromium-review.googlesource.com/757993
(cherry picked from commit b2eb4d0f85799f0fa063c5cca8e3deb32c765187)
Reviewed-on: https://chromium-review.googlesource.com/767968
Reviewed-by: Chirantan Ekbote <chirantan@chromium.org>
Tested-by: Jungshik Shin <jshin@chromium.org>
Commit-Queue: Jungshik Shin <jshin@chromium.org>

[modify] https://crrev.com/f45b5e6f55eea575f579a7462a2441c56573dcb1/sys-libs/timezone-data/Manifest
[rename] https://crrev.com/f45b5e6f55eea575f579a7462a2441c56573dcb1/sys-libs/timezone-data/files/timezone-data-2017c-makefile.patch
[rename] https://crrev.com/f45b5e6f55eea575f579a7462a2441c56573dcb1/sys-libs/timezone-data/timezone-data-2017c.ebuild

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/chrome/tools/buildspec/+/e723936372c98a79f5f5693cd0d37822cd56bdee

commit e723936372c98a79f5f5693cd0d37822cd56bdee
Author: Jungshik Shin <jungshik@google.com>
Date: Tue Nov 14 18:30:02 2017