Findit identified the culprit r577427 with confidence 70.0% in the config "chromium.chromiumos / linux-chromeos-dbg"
based on the flakiness trend:

https://findit-for-me.appspot.com/waterfall/flake?key=ag9zfmZpbmRpdC1mb3ItbWVyyQELEhdNYXN0ZXJGbGFrZUFuYWx5c2lzUm9vdCKSAWNocm9taXVtLmNocm9taXVtb3MvbGludXgtY2hyb21lb3MtZGJnLzcxNDAvdml6X2Jyb3dzZXJfdGVzdHMvUzJWNVltOWhjbVJQY0dWeVlYUnBiMjV6TDBacGJHVnpRWEJ3UW5KdmQzTmxjbFJsYzNRdVZHVnpkQzlyWlhsaWIyRnlaRVJsYkdWMFpVUnlhWFpsDAsSE01hc3RlckZsYWtlQW5hbHlzaXMYAQw

If the culprit above is wrong, please file a bug using this link and hit submit:
https://bugs.chromium.org/p/chromium/issues/entry?status=Unconfirmed&labels=Pri-1,Test-Findit-Wrong&components=Tools%3ETest%3EFindit%3EFlakiness&summary=%5BFindit%5D%20Flake%20Analyzer%20-%20Wrong%20result%20for%20KeyboardOperations/FilesAppBrowserTest.Test/keyboardDeleteDrive&comment=Link%20to%20Analysis%3A%20https://findit-for-me.appspot.com/waterfall/flake?key=ag9zfmZpbmRpdC1mb3ItbWVyyQELEhdNYXN0ZXJGbGFrZUFuYWx5c2lzUm9vdCKSAWNocm9taXVtLmNocm9taXVtb3MvbGludXgtY2hyb21lb3MtZGJnLzcxNDAvdml6X2Jyb3dzZXJfdGVzdHMvUzJWNVltOWhjbVJQY0dWeVlYUnBiMjV6TDBacGJHVnpRWEJ3UW5KdmQzTmxjbFJsYzNRdVZHVnpkQzlyWlhsaWIyRnlaRVJsYkdWMFpVUnlhWFpsDAsSE01hc3RlckZsYWtlQW5hbHlzaXMYAQw

Automatically posted by the findit-for-me app (https://goo.gl/Ot9f7N).

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d8fb3e8fd6e0b637be8af0180d96527541e6b69e

commit d8fb3e8fd6e0b637be8af0180d96527541e6b69e
Author: Rune Lillesveen <futhark@chromium.org>
Date: Tue Aug 07 11:17:52 2018

Disabled tests in chromeos dbg due to flakiness.

Only one of the subtests reported flaky, but didn't know how to disable
them separately.

TBR=noel@chromium.org

Bug:  871684 
Change-Id: Ie4f27cc5681ba3c6174853dbbfd16d1ba665c451
Reviewed-on: https://chromium-review.googlesource.com/1164958
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Commit-Queue: Rune Lillesveen <futhark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581194}
[modify] https://crrev.com/d8fb3e8fd6e0b637be8af0180d96527541e6b69e/chrome/browser/chromeos/file_manager/file_manager_browsertest.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/517b1e0eba215a6a6b9124d2f7ad6cd691278405

commit 517b1e0eba215a6a6b9124d2f7ad6cd691278405
Author: Noel Gordon <noel@chromium.org>
Date: Thu Aug 09 05:58:45 2018

Revert "Disabled tests in chromeos dbg due to flakiness."

This reverts commit d8fb3e8fd6e0b637be8af0180d96527541e6b69e.

Reason for revert: No evidence of flake on flakiness dashboard for
these tests in DEBUG, yet find.it said there was. Who's right?

Well, reverting this CL to find.it out (the cause was a bad v8 roll
by the looks).

Original change's description:
> Disabled tests in chromeos dbg due to flakiness.
>
> Only one of the subtests reported flaky, but didn't know how to disable
> them separately.
>
> TBR=noel@chromium.org
>
> Bug:  871684 
> Change-Id: Ie4f27cc5681ba3c6174853dbbfd16d1ba665c451
> Reviewed-on: https://chromium-review.googlesource.com/1164958
> Reviewed-by: Rune Lillesveen <futhark@chromium.org>
> Commit-Queue: Rune Lillesveen <futhark@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#581194}

TBR=futhark@chromium.org

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

Bug:  871684 
No-try: true
No-presubmit: true
Change-Id: Ibf9f9ee10ac3e1d37fb13c6b69ddac56071747a9
Reviewed-on: https://chromium-review.googlesource.com/1168842
Commit-Queue: Noel Gordon <noel@chromium.org>
Reviewed-by: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581803}
[modify] https://crrev.com/517b1e0eba215a6a6b9124d2f7ad6cd691278405/chrome/browser/chromeos/file_manager/file_manager_browsertest.cc

No evidence of flake on the flakiness dashbaord, as mentioned in review [1], so reverted #3 to find who's right. For all we know, t'was a bug in find.it: allowing this test to run again might tell us which.

[1] https://chromium-review.googlesource.com/c/chromium/src/+/1164958#message-75dba73026a96371abae5a3dc41872461c6dc0bb

 

OIC, this was on the Mash browser_tests.  Tip for gardeners: mash browser tests fails or flakes are disabled via a Mash bot exclusion file [1].

Anyho, we can dupe this now we know it is Mash.

[1] src/testing/buildbot/filters/mash.browser_tests.filter