Copying the crashing callstack from the logs above:

[20395:20395:0515/122612.193433:FATAL:chrome_app_list_model_updater.cc(511)] Check failed: chrome_item.
#0 0x0000045ae2fc base::debug::StackTrace::StackTrace()
#1 0x00000452b5cb logging::LogMessage::~LogMessage()
#2 0x0000077a90f7 ChromeAppListModelUpdater::OnItemUpdated()
#3 0x00000779b24a AppListClientImpl::OnItemUpdated()
#4 0x0000035b4840 ash::mojom::AppListClientStubDispatch::Accept()
#5 0x0000055dbe76 mojo::InterfaceEndpointClient::HandleValidatedMessage()


FWIW, my attempt to kick off a FindIt job failed - see  issue 843609 .


Surprisingly the test is listed in testing/buildbot/filters/mash.browser_tests.filter and I see that the flaking bot did include [1] this filter file in the test command:

./browser_tests --brave-new-test-launcher --test-launcher-bot-mode --cfi-diag=0 --enable-features=Mash --override-use-software-gl-for-tests --test-launcher-filter-file=../../testing/buildbot/filters/mash.browser_tests.filter --test-launcher-summary-output=/b/s/w/iouk24p5/output.json


I am not sure what options are left - maybe we can disable the test directly in chrome/browser/chromeos/file_manager/file_manager_browsertest.cc (but I only know how to disable it on all of CrOS - I don't know how to only disable on *mash* version of CrOS browser_tests...).


[1] https://logs.chromium.org/v/?s=chromium%2Fbuildbucket%2Fcr-buildbucket.appspot.com%2F8946436157677029600%2F%2B%2Fsteps%2Fmash_browser_tests__with_patch_%2F0%2Fstdout

The DCHECK is in ChromeAppListModelUpdater::OnItemUpdated and has nothing to do with MultiProfileFileManagerBrowserTest.BasicDrive test.

It looks like some racing condition that ash and chrome has different views of the app list items. Maybe just replace the DCHECK with an "if" and bail out in such case.

hejq@, could you check it out?

Will take a look

Detected 5 new flakes for test/step "MultiProfileFileManagerBrowserTest.BasicDrive". To see the actual flakes, please visit https://chromium-try-flakes.appspot.com/all_flake_occurrences?key=ahVzfmNocm9taXVtLXRyeS1mbGFrZXNyOAsSBUZsYWtlIi1NdWx0aVByb2ZpbGVGaWxlTWFuYWdlckJyb3dzZXJUZXN0LkJhc2ljRHJpdmUM. This message was posted automatically by the chromium-try-flakes app.

Bug assigned and actively being worked on, removing Sheriff label.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/61c4822171ec2c851dd714c9d894b8a9a4079a83

commit 61c4822171ec2c851dd714c9d894b8a9a4079a83
Author: Noel Gordon <noel@chromium.org>
Date: Tue May 29 04:15:07 2018

Disable MultiProfileFileManagerBrowserTest.* in Mash

crrev.com/562127 removed Mash exclusions for these tests. Restore the
exclusions since this tests flake on Mash due to issue 843429.

Bug:  847154 ,843429
Change-Id: I8e5cdd43592424fb3d2c313606059c139c6c14ea
Reviewed-on: https://chromium-review.googlesource.com/1075840
Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#562335}
[modify] https://crrev.com/61c4822171ec2c851dd714c9d894b8a9a4079a83/testing/buildbot/filters/mash.browser_tests.filter

Assigned to newcomer@.