I wonder if it would be reasonable to skip crash restore for kiosks, especially for auto-launched sessions - starting Chrome session from scratch should end up auto-launching the app again.

Right. Auto launch state is not preserved. On crash-n-restart, the app is launched here:
https://cs.chromium.org/chromium/src/chrome/browser/ui/startup/startup_browser_creator.cc?rcl=0&l=640

And we don't have whether this is an auto launch info there.

One possible way to preserve the info is to create a command line switch. Session manager would keep the switch for us. We figure out which app to relaunch via "--app-id". And probably can add a "--auto-launched" to keep the info across restarts.

Yeah, one way to fix this would be to let session manager know that current session is autolaunched, and have it append --auto-launched flag when Chrome is restarted (e.g. using SetFlagsForUser, though this could get a little tricky when kiosk session flags are non-empty, e.g. due to policy flags).

Another possibility would be to add a flag 'kiosk.restoreSessionAsAutoLaunched' (or something along these lines) to local_state, and set it appropriately when an app is launched. Then when restoring session from crash, autolaunched state could be initialized base on that flag's value.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/663f7dfaa3b96b353ade5b9ce6b7616e51ba73bb

commit 663f7dfaa3b96b353ade5b9ce6b7616e51ba73bb
Author: tbarzic <tbarzic@chromium.org>
Date: Wed Jan 25 23:51:01 2017

Restore auto-launched state on kiosk restart within session

When kiosk app is restarted within a kiosk session - e.g. due to crash,
app's auto-launched state has to be preserved. Previously auto-launched
state was kept only in memory - if kiosk was restarted, the information
would get lost.
This CL is attempt to fix the problem by preserving auto-launched state
by setting a user session scoped flag that indicates that the kiosk app
is auto-launched (newly introduced app-auto-launched). The flag will be
scoped to current used session, and will be passed to Chrome in a case
Chrome restarts withing the user session. On restart, the flag can be
used to deduce whether the kiosk app should be considered auto-launched
or not.

Note that when setting the auto-launched flag, it's important to
consider current set of policy defined flags - they should be
preserved when auto-launched flag is added to set of user flags.

BUG= 677340 

Review-Url: https://codereview.chromium.org/2639033002
Cr-Commit-Position: refs/heads/master@{#446166}

[modify] https://crrev.com/663f7dfaa3b96b353ade5b9ce6b7616e51ba73bb/chrome/browser/chromeos/app_mode/kiosk_app_manager.cc
[modify] https://crrev.com/663f7dfaa3b96b353ade5b9ce6b7616e51ba73bb/chrome/browser/chromeos/app_mode/kiosk_app_manager.h
[delete] https://crrev.com/0d3069a5ad51f4d337927f5a1ed4e0945488d7c1/chrome/browser/chromeos/app_mode/kiosk_crash_restore_browsertest.cc
[add] https://crrev.com/663f7dfaa3b96b353ade5b9ce6b7616e51ba73bb/chrome/browser/chromeos/login/auto_launched_kiosk_browsertest.cc
[modify] https://crrev.com/663f7dfaa3b96b353ade5b9ce6b7616e51ba73bb/chrome/browser/chromeos/login/session/user_session_manager.cc
[modify] https://crrev.com/663f7dfaa3b96b353ade5b9ce6b7616e51ba73bb/chrome/browser/chromeos/login/users/chrome_user_manager_impl.cc
[modify] https://crrev.com/663f7dfaa3b96b353ade5b9ce6b7616e51ba73bb/chrome/test/BUILD.gn
[modify] https://crrev.com/663f7dfaa3b96b353ade5b9ce6b7616e51ba73bb/chromeos/chromeos_switches.cc
[modify] https://crrev.com/663f7dfaa3b96b353ade5b9ce6b7616e51ba73bb/chromeos/chromeos_switches.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/92ebeda78b7d6e27e7afa0ef44c82140ce682441

commit 92ebeda78b7d6e27e7afa0ef44c82140ce682441
Author: kjellander <kjellander@chromium.org>
Date: Thu Jan 26 05:46:42 2017

Revert of Restore auto-launched state on kiosk restart within session (patchset #6 id:100001 of https://codereview.chromium.org/2639033002/ )

Reason for revert:
browser_tests test AutoLaunchedKioskTest.PRE_CrashRestore starts timing out reliably with this CL, starting with https://build.chromium.org/p/chromium.chromiumos/builders/Linux%20ChromiumOS%20Tests%20%281%29/builds/32762

Original issue's description:
> Restore auto-launched state on kiosk restart within session
>
> When kiosk app is restarted within a kiosk session - e.g. due to crash,
> app's auto-launched state has to be preserved. Previously auto-launched
> state was kept only in memory - if kiosk was restarted, the information
> would get lost.
> This CL is attempt to fix the problem by preserving auto-launched state
> by setting a user session scoped flag that indicates that the kiosk app
> is auto-launched (newly introduced app-auto-launched). The flag will be
> scoped to current used session, and will be passed to Chrome in a case
> Chrome restarts withing the user session. On restart, the flag can be
> used to deduce whether the kiosk app should be considered auto-launched
> or not.
>
> Note that when setting the auto-launched flag, it's important to
> consider current set of policy defined flags - they should be
> preserved when auto-launched flag is added to set of user flags.
>
> BUG= 677340 
>
> Review-Url: https://codereview.chromium.org/2639033002
> Cr-Commit-Position: refs/heads/master@{#446166}
> Committed: https://chromium.googlesource.com/chromium/src/+/663f7dfaa3b96b353ade5b9ce6b7616e51ba73bb

TBR=xiyuan@chromium.org,tbarzic@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG= 677340 

Review-Url: https://codereview.chromium.org/2658773002
Cr-Commit-Position: refs/heads/master@{#446240}

[modify] https://crrev.com/92ebeda78b7d6e27e7afa0ef44c82140ce682441/chrome/browser/chromeos/app_mode/kiosk_app_manager.cc
[modify] https://crrev.com/92ebeda78b7d6e27e7afa0ef44c82140ce682441/chrome/browser/chromeos/app_mode/kiosk_app_manager.h
[add] https://crrev.com/92ebeda78b7d6e27e7afa0ef44c82140ce682441/chrome/browser/chromeos/app_mode/kiosk_crash_restore_browsertest.cc
[delete] https://crrev.com/99fb0a7ab0aa355d6d2bd17ca0d6940b57ec44b4/chrome/browser/chromeos/login/auto_launched_kiosk_browsertest.cc
[modify] https://crrev.com/92ebeda78b7d6e27e7afa0ef44c82140ce682441/chrome/browser/chromeos/login/session/user_session_manager.cc
[modify] https://crrev.com/92ebeda78b7d6e27e7afa0ef44c82140ce682441/chrome/browser/chromeos/login/users/chrome_user_manager_impl.cc
[modify] https://crrev.com/92ebeda78b7d6e27e7afa0ef44c82140ce682441/chrome/test/BUILD.gn
[modify] https://crrev.com/92ebeda78b7d6e27e7afa0ef44c82140ce682441/chromeos/chromeos_switches.cc
[modify] https://crrev.com/92ebeda78b7d6e27e7afa0ef44c82140ce682441/chromeos/chromeos_switches.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c6b3e0d3813eb1bc13bbaba9e5d19054890606c7

commit c6b3e0d3813eb1bc13bbaba9e5d19054890606c7
Author: tbarzic <tbarzic@chromium.org>
Date: Thu Jan 26 20:19:14 2017

Restore auto-launched state on kiosk restart within session

When kiosk app is restarted within a kiosk session - e.g. due to crash,
app's auto-launched state has to be preserved. Previously auto-launched
state was kept only in memory - if kiosk was restarted, the information
would get lost.
This CL is attempt to fix the problem by preserving auto-launched state
by setting a user session scoped flag that indicates that the kiosk app
is auto-launched (newly introduced app-auto-launched). The flag will be
scoped to current used session, and will be passed to Chrome in a case
Chrome restarts withing the user session. On restart, the flag can be
used to deduce whether the kiosk app should be considered auto-launched
or not.

Note that when setting the auto-launched flag, it's important to
consider current set of policy defined flags - they should be
preserved when auto-launched flag is added to set of user flags.

BUG= 677340 

Review-Url: https://codereview.chromium.org/2639033002
Cr-Original-Commit-Position: refs/heads/master@{#446166}
Committed: https://chromium.googlesource.com/chromium/src/+/663f7dfaa3b96b353ade5b9ce6b7616e51ba73bb
Review-Url: https://codereview.chromium.org/2639033002
Cr-Commit-Position: refs/heads/master@{#446427}

[modify] https://crrev.com/c6b3e0d3813eb1bc13bbaba9e5d19054890606c7/chrome/browser/chromeos/app_mode/kiosk_app_manager.cc
[modify] https://crrev.com/c6b3e0d3813eb1bc13bbaba9e5d19054890606c7/chrome/browser/chromeos/app_mode/kiosk_app_manager.h
[delete] https://crrev.com/a02187345a2ce4d5f929816aaddb1369a0afbed1/chrome/browser/chromeos/app_mode/kiosk_crash_restore_browsertest.cc
[add] https://crrev.com/c6b3e0d3813eb1bc13bbaba9e5d19054890606c7/chrome/browser/chromeos/login/auto_launched_kiosk_browsertest.cc
[modify] https://crrev.com/c6b3e0d3813eb1bc13bbaba9e5d19054890606c7/chrome/browser/chromeos/login/session/user_session_manager.cc
[modify] https://crrev.com/c6b3e0d3813eb1bc13bbaba9e5d19054890606c7/chrome/browser/chromeos/login/users/chrome_user_manager_impl.cc
[modify] https://crrev.com/c6b3e0d3813eb1bc13bbaba9e5d19054890606c7/chrome/test/BUILD.gn
[modify] https://crrev.com/c6b3e0d3813eb1bc13bbaba9e5d19054890606c7/chromeos/chromeos_switches.cc
[modify] https://crrev.com/c6b3e0d3813eb1bc13bbaba9e5d19054890606c7/chromeos/chromeos_switches.h

requesting merge - note that this should fix KioskCrashRestoreTest breakage (https://bugs.chromium.org/p/chromium/issues/detail?id=689100) - the cl fix for this issue removes the test in question

This bug requires manual review: Reverts referenced in bugdroid comments after merge request.
Please contact the milestone owner if you have questions.
Owners: amineer@(clank), cmasso@(bling), ketakid@(cros), govind@(desktop)

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