The flakiness dashboard shows this test pretty consistently timing out then passing. The earliest flake on chromium-try-flakes points at the flake first occurring for https://codereview.chromium.org/2438773003/#ps310001 so maybe a build dependency problem?

Disabling the test in https://codereview.chromium.org/2852933002.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/91f64acccbfe592af367f79ae74649d520528f0b

commit 91f64acccbfe592af367f79ae74649d520528f0b
Author: suzyh <suzyh@chromium.org>
Date: Mon May 01 05:03:36 2017

Disable flaky CommandLineExtensionsDontLoad test

TBR=emaxx@chromium.org
BUG= 716727 

Review-Url: https://codereview.chromium.org/2852933002
Cr-Commit-Position: refs/heads/master@{#468286}

[modify] https://crrev.com/91f64acccbfe592af367f79ae74649d520528f0b/chrome/browser/extensions/extension_startup_browsertest.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/606b2b5d25564f187a843d25e5c2998d4ad2c04e

commit 606b2b5d25564f187a843d25e5c2998d4ad2c04e
Author: suzyh <suzyh@chromium.org>
Date: Mon May 01 05:30:57 2017

Revert of Disable flaky CommandLineExtensionsDontLoad test (patchset #1 id:1 of https://codereview.chromium.org/2852933002/ )

Reason for revert:
Speculatively reverting due to build failure on Mac https://build.chromium.org/p/chromium/builders/Mac/builds/26841

Original issue's description:
> Disable flaky CommandLineExtensionsDontLoad test
>
> TBR=emaxx@chromium.org
> BUG= 716727 
>
> Review-Url: https://codereview.chromium.org/2852933002
> Cr-Commit-Position: refs/heads/master@{#468286}
> Committed: https://chromium.googlesource.com/chromium/src/+/91f64acccbfe592af367f79ae74649d520528f0b

TBR=emaxx@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG= 716727 

Review-Url: https://codereview.chromium.org/2855553002
Cr-Commit-Position: refs/heads/master@{#468290}

[modify] https://crrev.com/606b2b5d25564f187a843d25e5c2998d4ad2c04e/chrome/browser/extensions/extension_startup_browsertest.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/78f1ed5b275c87a998bcb2c4d0d79af92316394d

commit 78f1ed5b275c87a998bcb2c4d0d79af92316394d
Author: suzyh <suzyh@chromium.org>
Date: Mon May 01 06:55:51 2017

Reland of Disable flaky CommandLineExtensionsDontLoad test (patchset #1 id:1 of https://codereview.chromium.org/2855553002/ )

Reason for revert:
Build failure causing original revert seems to have been a flake.

Original issue's description:
> Revert of Disable flaky CommandLineExtensionsDontLoad test (patchset #1 id:1 of https://codereview.chromium.org/2852933002/ )
>
> Reason for revert:
> Speculatively reverting due to build failure on Mac https://build.chromium.org/p/chromium/builders/Mac/builds/26841
>
> Original issue's description:
> > Disable flaky CommandLineExtensionsDontLoad test
> >
> > TBR=emaxx@chromium.org
> > BUG= 716727 
> >
> > Review-Url: https://codereview.chromium.org/2852933002
> > Cr-Commit-Position: refs/heads/master@{#468286}
> > Committed: https://chromium.googlesource.com/chromium/src/+/91f64acccbfe592af367f79ae74649d520528f0b
>
> TBR=emaxx@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG= 716727 
>
> Review-Url: https://codereview.chromium.org/2855553002
> Cr-Commit-Position: refs/heads/master@{#468290}
> Committed: https://chromium.googlesource.com/chromium/src/+/606b2b5d25564f187a843d25e5c2998d4ad2c04e

TBR=emaxx@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG= 716727 

Review-Url: https://codereview.chromium.org/2848223002
Cr-Commit-Position: refs/heads/master@{#468300}

[modify] https://crrev.com/78f1ed5b275c87a998bcb2c4d0d79af92316394d/chrome/browser/extensions/extension_startup_browsertest.cc

Thanks. I'll investigate what's wrong with the test.

I believe that this flake, and some related file test failures[1], are caused by the test suite hanging.

I'm working on an update via  issue 716476  which may address this. I'll try them with my patch.

[1]Other related flakes:

ContentVerifierPolicyTest.FailedUpdateRetries
CreateNewFolder/FileManagerBrowserTest.Test/3
Delete/FileManagerBrowserTest.Test/0
Delete/FileManagerBrowserTest.Test/1
DirectoryTreeContextMenu/FileManagerBrowserTest.Test/0
DirectoryTreeContextMenu/FileManagerBrowserTest.Test/22
DirectoryTreeContextMenu/FileManagerBrowserTest.Test/24
DriveSpecific/FileManagerBrowserTest.Test/0
DriveSpecific/FileManagerBrowserTest.Test/1
DriveSpecific/FileManagerBrowserTest.Test/2
ExperimentalAppWindowApiTest.SetIcon
OpenAudioFiles/FileManagerBrowserTest.Test/8
OpenFileDialog/FileManagerBrowserTest.Test/4
OpenFileDialog/FileManagerBrowserTest.Test/5
PrintPreviewDestinationSearchTest.Select
Providers/FileManagerBrowserTest.Test/0
Providers/FileManagerBrowserTest.Test/1
ShowGridView/FileManagerBrowserTest.Test/0
ShowGridView/FileManagerBrowserTest.Test/1

Thanks Jonathan!

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8646d4398a1a827789b0805403f9e3e2c2c7e869

commit 8646d4398a1a827789b0805403f9e3e2c2c7e869
Author: Maksim Ivanov <emaxx@chromium.org>
Date: Fri May 19 23:57:54 2017

Reenable test CommandLineExtensionsDontLoad everywhere except on Mash

The ExtensionsLoadTestWithLoginScreenApps.CommandLineExtensionsDontLoad
test was failing in mash_browsertests. According to some investigation,
it may be due to the problem not with the test itself, but with the test
suite (see  https://crbug.com/716727#c6 ).

Therefore enabling the test, but with blacklisting it from running in
mash_browsertests.

Bug:  716727 
Change-Id: I0860b9efbcfd5a333464a2567273a962d0957a5e
Reviewed-on: https://chromium-review.googlesource.com/503351
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Reviewed-by: Jonathan Ross <jonross@chromium.org>
Commit-Queue: Maksim Ivanov <emaxx@chromium.org>
Cr-Commit-Position: refs/heads/master@{#473385}
[modify] https://crrev.com/8646d4398a1a827789b0805403f9e3e2c2c7e869/chrome/browser/extensions/extension_startup_browsertest.cc
[modify] https://crrev.com/8646d4398a1a827789b0805403f9e3e2c2c7e869/testing/buildbot/filters/mash.browser_tests.filter