Issue 256489  has been merged into this issue.

A couple of ideas (potentially crazy. might be a bit expensive):

While/before forking, ask the browser process for the time zone ID (Olson) and update the ICU default time zone in zygote. A new tz id can be compared with the current default. If they agree, it'll not be updated. This has to happen every time render process is forked from zygote process (instead of only 'on tz change'). 

A much better way would be to send down a new Olson tz ID to Zygote ON a tz update (from TimeZone monitor) if we can get hold of a zygote_host. A recent decoupling of TZMonitor from content might or might not make this more difficult than before ( bug 612341 ). 

The following revision refers to this bug:
  https://chromium.googlesource.com/v8/v8.git/+/28ef8dc7009d57de2782668ed00dff34e31dee2d

commit 28ef8dc7009d57de2782668ed00dff34e31dee2d
Author: Jungshik Shin <jshin@chromium.org>
Date: Wed Oct 11 23:21:37 2017

Revert "Enable icu-timezone-data by default"

This reverts commit d9a25842d3aba82ead5e06c7fd7cb4896e6ad202.

Reason for revert: 

I'm reverting this CL for a few reasons. #2 is the most significant and I should have thought of that before making a switch. Sorry for that.   

1) perf-regression:  http://crbug.com/769706 
2)  http://crbug.com/612010  : ICU timezone update is not propagated to zygote process so that new tabs will hold on to an old timezone even after a timezone change on Linux and Chrome OS. 
3)  http://crbug.com/754053  : OS timezone detection issues on macOS 10.13, Ubutu 16, RHEL 7, SuSe Linux 12 or newer. ; it's being fixed. So, it actually ok.  
4)  http://crbug.com/771868  : timezone wrong in gmail: If it's due to #3, we're fine because it's fixed. If not, we need to look more.

Original change's description:
> Enable icu-timezone-data by default
> 
> This will introduce a new behavior on POSIX(-like) platforms. Timezone
> names inside parentheses after GMT offset will not be 3-4 letter
> abbreviation any longer. They'll be human-readable names in the current
> default locale. This matches the current Windows behavior.
> 
> new Date(2017, 5, 22).toString()
> new Date(2017, 11, 22).toString()
> 
> Current:
> 
> Thu Jun 22 2017 00:00:00 GMT-0700 (PDT)
> Fri Dec 22 2017 00:00:00 GMT-0800 (PST)
> 
> New in en-US locale:
> 
> Thu Jun 22 2017 00:00:00 GMT-0700 (Pacific Daylight Time)
> Fri Dec 22 2017 00:00:00 GMT-0800 (Pacific Standard Time)
> 
> New in German locale:
> 
> Thu Jun 22 2017 00:00:00 GMT-0700 (Nordamerikanische Westküsten-Sommerzeit)
> Fri Dec 22 2017 00:00:00 GMT-0800 (Nordamerikanische Westküsten-Normalzeit)
> 
> BUG= v8:6031 ,  v8:2137 , v8:6076
> TEST=mjsunit/icu-date-lord-howe.js, mjsunit/icu-date-to-string.js
> 
> Change-Id: I4e7fd8b3ddae5c7779e220c4c101e45904fcdc01
> Reviewed-on: https://chromium-review.googlesource.com/625164
> Commit-Queue: Jungshik Shin <jshin@chromium.org>
> Reviewed-by: Daniel Ehrenberg <littledan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#47953}

TBR=adamk@chromium.org,littledan@chromium.org,jshin@chromium.org

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

Bug:  v8:6031 ,  v8:2137 , v8:6076,  chromium:769706 ,  chromium:612010 ,  chromium:771868 
Change-Id: I60d75467ee21975d3a235344b01c0d2d44a7da96
Reviewed-on: https://chromium-review.googlesource.com/713404
Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Jungshik Shin <jshin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48478}
[modify] https://crrev.com/28ef8dc7009d57de2782668ed00dff34e31dee2d/src/flag-definitions.h

We are creating the 6.3 branch today. Please merge this on the branch afterwards.

(the revert)

From 771868,  macOS seems to have begun to show a similar symptom:

-----------cut----here
In a new tab (opened after a timezone change), I got this. Note that timeZone is not defined. 

> var nf= new Intl.DateTimeFormat("en")

> nf.resolvedOptions()
{locale: "en", numberingSystem: "latn", calendar: "gregory", timeZone: undefined, year: "numeric", …}

In an existing tab, I got this (note that timeZOne is correct) 

{locale: "en", numberingSystem: "latn", calendar: "gregory", timeZone: "Australia/Sydney", year: "numeric", …}

Hmm.... this is  bug 612010 , but that bug didn't exist on macOS. It's only for Chrome OS and Linux. So, something must have happened recently to make it an issue on macOS.

Does macOS now have a zygote process?   
--------cut-----here --------

This issue has been approved for a merge. Please merge the fix to any appropriate branches as soon as possible!

If all merges have been completed, please remove any remaining Merge-Approved labels from this issue.

Thanks for your time! To disable nags, add the Disable-Nags label.

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

The following revision refers to this bug:
  https://chromium.googlesource.com/v8/v8.git/+/d7343703bc6a3c1dbd5ead201186c520ffc9e47b

commit d7343703bc6a3c1dbd5ead201186c520ffc9e47b
Author: Jungshik Shin <jshin@chromium.org>
Date: Mon Oct 16 20:43:16 2017

Merged: Revert "Enable icu-timezone-data by default"

This reverts commit d9a25842d3aba82ead5e06c7fd7cb4896e6ad202.
This is for 6.3 branch (to go with Chromium 63 branch). 

Reason for revert:

I'm reverting this CL for a few reasons. #2 is the most significant and
I should have thought of that before making a switch. Sorry for that.

1) perf-regression:  http://crbug.com/769706 
2)  http://crbug.com/612010  : ICU timezone update is not propagated to
zygote process so that new tabs will hold on to an old timezone even
after a timezone change on Linux and Chrome OS.

3)   http://crbug.com/754053   : OS timezone detection issues on macOS
10.13, Ubutu 16, RHEL 7, SuSe Linux 12 or newer. ; it's being fixed. So,
it actually ok.

4)   http://crbug.com/771868   : timezone wrong in gmail: If it's due to

Revision: 28ef8dc7009d

BUG= chromium:612010 , chromium:769706 , chromium:771868 , v8:2137 , v8:6031 ,v8:6076
LOG=N
NOTRY=true
NOPRESUBMIT=true
NOTREECHECKS=true
R=adamk@chromium.org, hablich@chromium.org

Change-Id: Id0093c2bc69e5bc1d3b7147b7bbcc633ed625a45
Reviewed-on: https://chromium-review.googlesource.com/721919
Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Jungshik Shin <jshin@chromium.org>
Cr-Commit-Position: refs/branch-heads/6.3@{#7}
Cr-Branched-From: 094a7c93dcdcd921de3883ba4674b7e1a0feffbe-refs/heads/6.3.292@{#1}
Cr-Branched-From: 18b8fbb528a8021e04a029e06eafee50b918bce0-refs/heads/master@{#48432}
[modify] https://crrev.com/d7343703bc6a3c1dbd5ead201186c520ffc9e47b/src/flag-definitions.h

The following revision refers to this bug:
  https://chromium.googlesource.com/v8/v8.git/+/3b1cfa38bcd616609f263ac3b6721c0214c45d19

commit 3b1cfa38bcd616609f263ac3b6721c0214c45d19
Author: Michael Hablich <hablich@chromium.org>
Date: Tue Oct 17 16:11:43 2017

Revert "Merged: Revert "Enable icu-timezone-data by default""

This reverts commit d7343703bc6a3c1dbd5ead201186c520ffc9e47b.

Reason for revert: broke some branch builders like https://build.chromium.org/p/client.v8.branches/builders/V8%20arm%20-%20sim%20-%20beta%20branch%20-%20debug

Original change's description:
> Merged: Revert "Enable icu-timezone-data by default"
> 
> This reverts commit d9a25842d3aba82ead5e06c7fd7cb4896e6ad202.
> This is for 6.3 branch (to go with Chromium 63 branch). 
> 
> Reason for revert:
> 
> I'm reverting this CL for a few reasons. #2 is the most significant and
> I should have thought of that before making a switch. Sorry for that.
> 
> 1) perf-regression:  http://crbug.com/769706 
> 2)  http://crbug.com/612010  : ICU timezone update is not propagated to
> zygote process so that new tabs will hold on to an old timezone even
> after a timezone change on Linux and Chrome OS.
> 
> 3)   http://crbug.com/754053   : OS timezone detection issues on macOS
> 10.13, Ubutu 16, RHEL 7, SuSe Linux 12 or newer. ; it's being fixed. So,
> it actually ok.
> 
> 4)   http://crbug.com/771868   : timezone wrong in gmail: If it's due to
> 
> Revision: 28ef8dc7009d
> 
> BUG= chromium:612010 , chromium:769706 , chromium:771868 , v8:2137 , v8:6031 ,v8:6076
> LOG=N
> NOTRY=true
> NOPRESUBMIT=true
> NOTREECHECKS=true
> R=​adamk@chromium.org, hablich@chromium.org
> 
> Change-Id: Id0093c2bc69e5bc1d3b7147b7bbcc633ed625a45
> Reviewed-on: https://chromium-review.googlesource.com/721919
> Reviewed-by: Adam Klein <adamk@chromium.org>
> Commit-Queue: Jungshik Shin <jshin@chromium.org>
> Cr-Commit-Position: refs/branch-heads/6.3@{#7}
> Cr-Branched-From: 094a7c93dcdcd921de3883ba4674b7e1a0feffbe-refs/heads/6.3.292@{#1}
> Cr-Branched-From: 18b8fbb528a8021e04a029e06eafee50b918bce0-refs/heads/master@{#48432}

TBR=adamk@chromium.org,hablich@chromium.org,jshin@chromium.org

Change-Id: I8b30f8f9c63b93cb000facbf910ed111ca3f9ab2
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug:  chromium:612010 ,  chromium:769706 ,  chromium:771868 ,  v8:2137 ,  v8:6031 , v8:6076
Reviewed-on: https://chromium-review.googlesource.com/723324
Reviewed-by: Michael Hablich <hablich@chromium.org>
Commit-Queue: Michael Hablich <hablich@chromium.org>
Cr-Commit-Position: refs/branch-heads/6.3@{#18}
Cr-Branched-From: 094a7c93dcdcd921de3883ba4674b7e1a0feffbe-refs/heads/6.3.292@{#1}
Cr-Branched-From: 18b8fbb528a8021e04a029e06eafee50b918bce0-refs/heads/master@{#48432}
[modify] https://crrev.com/3b1cfa38bcd616609f263ac3b6721c0214c45d19/src/flag-definitions.h

The following revision refers to this bug:
  https://chromium.googlesource.com/v8/v8.git/+/9685d9c25a45f7902fe6250b64ca61abeea1e9f5

commit 9685d9c25a45f7902fe6250b64ca61abeea1e9f5
Author: Jungshik Shin <jshin@chromium.org>
Date: Tue Oct 17 20:55:47 2017

Revert "Revert "Merged: Revert "Enable icu-timezone-data by default"""

This reverts commit 3b1cfa38bcd616609f263ac3b6721c0214c45d19.

Reason for revert: ICU was not rolled in 6.3 branch leading invalid-locale test failure (that was added to test an ICU fix). Now, ICU is rolled in 6.3 branch ( https://chromium-review.googlesource.com/c/v8/v8/+/723564 ). 

Original change's description:
> Revert "Merged: Revert "Enable icu-timezone-data by default""
> 
> This reverts commit d7343703bc6a3c1dbd5ead201186c520ffc9e47b.
> 
> Reason for revert: broke some branch builders like https://build.chromium.org/p/client.v8.branches/builders/V8%20arm%20-%20sim%20-%20beta%20branch%20-%20debug
> 
> Original change's description:
> > Merged: Revert "Enable icu-timezone-data by default"
> > 
> > This reverts commit d9a25842d3aba82ead5e06c7fd7cb4896e6ad202.
> > This is for 6.3 branch (to go with Chromium 63 branch). 
> > 
> > Reason for revert:
> > 
> > I'm reverting this CL for a few reasons. #2 is the most significant and
> > I should have thought of that before making a switch. Sorry for that.
> > 
> > 1) perf-regression:  http://crbug.com/769706 
> > 2)  http://crbug.com/612010  : ICU timezone update is not propagated to
> > zygote process so that new tabs will hold on to an old timezone even
> > after a timezone change on Linux and Chrome OS.
> > 
> > 3)   http://crbug.com/754053   : OS timezone detection issues on macOS
> > 10.13, Ubutu 16, RHEL 7, SuSe Linux 12 or newer. ; it's being fixed. So,
> > it actually ok.
> > 
> > 4)   http://crbug.com/771868   : timezone wrong in gmail: If it's due to
> > 
> > Revision: 28ef8dc7009d
> > 
> > BUG= chromium:612010 , chromium:769706 , chromium:771868 , v8:2137 , v8:6031 ,v8:6076
> > LOG=N
> > NOTRY=true
> > NOPRESUBMIT=true
> > NOTREECHECKS=true
> > R=​adamk@chromium.org, hablich@chromium.org
> > 
> > Change-Id: Id0093c2bc69e5bc1d3b7147b7bbcc633ed625a45
> > Reviewed-on: https://chromium-review.googlesource.com/721919
> > Reviewed-by: Adam Klein <adamk@chromium.org>
> > Commit-Queue: Jungshik Shin <jshin@chromium.org>
> > Cr-Commit-Position: refs/branch-heads/6.3@{#7}
> > Cr-Branched-From: 094a7c93dcdcd921de3883ba4674b7e1a0feffbe-refs/heads/6.3.292@{#1}
> > Cr-Branched-From: 18b8fbb528a8021e04a029e06eafee50b918bce0-refs/heads/master@{#48432}
> 
> TBR=adamk@chromium.org,hablich@chromium.org,jshin@chromium.org
> 
> Change-Id: I8b30f8f9c63b93cb000facbf910ed111ca3f9ab2
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug:  chromium:612010 ,  chromium:769706 ,  chromium:771868 ,  v8:2137 ,  v8:6031 , v8:6076
> Reviewed-on: https://chromium-review.googlesource.com/723324
> Reviewed-by: Michael Hablich <hablich@chromium.org>
> Commit-Queue: Michael Hablich <hablich@chromium.org>
> Cr-Commit-Position: refs/branch-heads/6.3@{#18}
> Cr-Branched-From: 094a7c93dcdcd921de3883ba4674b7e1a0feffbe-refs/heads/6.3.292@{#1}
> Cr-Branched-From: 18b8fbb528a8021e04a029e06eafee50b918bce0-refs/heads/master@{#48432}

TBR=adamk@chromium.org,hablich@chromium.org,jshin@chromium.org

Change-Id: I8f712f1e6eb1f14c703ffe9f1d63d23b4b4bb08e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug:  chromium:612010 ,  chromium:769706 ,  chromium:771868 ,  v8:2137 ,  v8:6031 , v8:6076
Reviewed-on: https://chromium-review.googlesource.com/723962
Reviewed-by: Michael Hablich <hablich@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Jungshik Shin <jshin@chromium.org>
Cr-Commit-Position: refs/branch-heads/6.3@{#21}
Cr-Branched-From: 094a7c93dcdcd921de3883ba4674b7e1a0feffbe-refs/heads/6.3.292@{#1}
Cr-Branched-From: 18b8fbb528a8021e04a029e06eafee50b918bce0-refs/heads/master@{#48432}
[modify] https://crrev.com/9685d9c25a45f7902fe6250b64ca61abeea1e9f5/src/flag-definitions.h

This issue has been approved for a merge. Please merge the fix to any appropriate branches as soon as possible!

If all merges have been completed, please remove any remaining Merge-Approved labels from this issue.

Thanks for your time! To disable nags, add the Disable-Nags label.

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

note to self: 
I had a fresh look at this issue. One promising place we can pass the Olson timezone id at the time fork (instead of at the time of the zygote process creation) is (not surprisingly) ZygoteCommunication:;ForkRequest ( https://cs.chromium.org/chromium/src/content/browser/zygote_host/zygote_communication_linux.cc?rcl=ea59ac93019e22b05026167b2b58265d9e7fca51&l=87 ). 

The receiving end is 
https://cs.chromium.org/chromium/src/content/zygote/zygote_linux.cc?rcl=b297d7f211af679da382b691cd0ebe286c0a7c65&l=270 .

This is not ideal because tzid is sent down and set in a new render process even when there's no timezone change, but should work. 

An alternative is to use ZygoteHandle (ZygoteCommunication) via ZygoteHostImpl to send a tz update msg from TimezoneMonitor. This has an advantage of being run only on a timezone change.

Hmm... TimezoneMonitor is now in service/devices and does not depend on content/ .

OTOH, one advantage of the approach in comment 14 is that it can respect TZ environment variable (as used by some embedders / headless Blink).  Adding +dats@ for that. 

WIth a CL at https://chromium-review.googlesource.com/c/chromium/src/+/764036, the following works:

* Launch chrome 
* Go to http://jungshik.github.io/cr/bugs/520783.html
* Change the tz to a zone different from the current zone
$ sudo timedatectl set-timezone Asia/Seoul
* Press 'recheck' button in the page above to check a tz change is reflected.
   THis part already works without the CL above. 
* Make a new tab and go to http://jungshik.github.io/cr/bugs/520783.html
* Check the timezone and the zone offset. They should be for a new timezone. This part
did not work before. The CL above fixes it. 

$ sudo timedatectl set-timezone Asia/Seoul

The above is for Ubuntu. 
On other Linux distros, changing a symlink target of /etc/localtime to a zonefile in /usr/share/timezone/ works, too. 

On CrOS, settings can be used to change the timezone to test. 

http://jungshik.github.io/cr/bugs/520783.html : Only lines 4 and 8 are relevant to this bug. 

Lines 1 and 2 are not unless icu-timezone-data is passed to v8 via --js-flags cmdline flag or  bug v8:6031  is resolved (icu-timezone-data becomes enabled by default). 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ecc9a74e8a6642d68f20ced81bc515e7e32fc38d

commit ecc9a74e8a6642d68f20ced81bc515e7e32fc38d
Author: Jungshik Shin <jshin@chromium.org>
Date: Tue Nov 14 07:25:06 2017

Pass the current timezone id to Zygote on fork

On a timezone change, existing renderer processes are notified of the
change, but the zygote process is not notified, which leads a new tab
on Linux to hold on to the old timezone after a timezone change.

To fix that, this CL passes the current timezone id (Olson) to the zygote
process and lets it reset the ICU timezone before forking.

Bug:  612010 
Test: See comment 16 in the bug
Change-Id: I0962e3d8c29ad5494fc3f9cd4f9d1d62588b7003
Reviewed-on: https://chromium-review.googlesource.com/764036
Commit-Queue: Jungshik Shin <jshin@chromium.org>
Reviewed-by: Julien Tinnes <jln@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#516222}
[modify] https://crrev.com/ecc9a74e8a6642d68f20ced81bc515e7e32fc38d/content/browser/zygote_host/zygote_communication_linux.cc
[modify] https://crrev.com/ecc9a74e8a6642d68f20ced81bc515e7e32fc38d/content/zygote/zygote_linux.cc

Tested the issue using #64.0.3269.0 on Linux Ubuntu 14.04 as per the steps mentioned in comment #0. Observed the Timezone is changing accrodingly.

Note: Issue is still obserevd in #64.0.3265.0/10129.0.0 canary-channel kip.

Please find the screencast for the same. Hence adding Verified labels for Linux.

Thanks!!

Deleted: Screenshot from 2017-11-15 06:35:34.png 94.3 KB

	Screenshot from 2017-11-15 06:35:34.png 94.3 KB View Download

Thanks for verifying the fix.