I didn't find a culprit CL, I'll disable the test.

lucmult@ or noel@, could you take a look?

CL to disable the test is in the CQ now: https://chromium-review.googlesource.com/c/chromium/src/+/1188763

Removing Sheriff-Chromium label.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b74fad869155cda83ae31ee05a22fcfc4bc68445

commit b74fad869155cda83ae31ee05a22fcfc4bc68445
Author: Scott Little <sclittle@chromium.org>
Date: Fri Aug 24 18:29:51 2018

Disable failing file manager browsertest.

This test is failing on the MSan bot, so it's being temporarily
disabled:
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Linux%20ChromiumOS%20MSan%20Tests/8307

TBR=lucmult@chromium.org

Bug:  877557 
Change-Id: If5ed2948b2266591fd5d76aa3c305455d02ee9a5
Reviewed-on: https://chromium-review.googlesource.com/1188763
Reviewed-by: Scott Little <sclittle@chromium.org>
Commit-Queue: Scott Little <sclittle@chromium.org>
Cr-Commit-Position: refs/heads/master@{#585912}
[modify] https://crrev.com/b74fad869155cda83ae31ee05a22fcfc4bc68445/chrome/browser/chromeos/file_manager/file_manager_browsertest.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/24056c1bd58950370f03fa3c1d1733271ad4ea51

commit 24056c1bd58950370f03fa3c1d1733271ad4ea51
Author: Noel Gordon <noel@chromium.org>
Date: Sat Aug 25 05:36:04 2018

Improve KeyboardOperations test: renameNewFolderDownloads

Test is flaky on the slower bots MSAN/ASAN with selection failures. Add
more steps, add step result checking. Use more precise selectors on the
file list operations. Do an initial focus on the file list. Load photos
only in SetUpAndWaitUntilReady (for more speed). Check that the renamed
folder is shown in the directory tree and the file list.

The new steps are cargo-culted from the create_new_folder.js test which
is a similar test, with similar selection flakes (fixed on CL:1186008).

Tbr: lucmult
Bug:  874954 , 877557 
Change-Id: Ib9f988e0dadafd0a52bd509ae664aa3cbfe395fb
Reviewed-on: https://chromium-review.googlesource.com/1188178
Reviewed-by: Noel Gordon <noel@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#586122}
[modify] https://crrev.com/24056c1bd58950370f03fa3c1d1733271ad4ea51/ui/file_manager/integration_tests/file_manager/keyboard_operations.js

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3ce1fba20a3f1b5035726c0f7b9674744e72b0bb

commit 3ce1fba20a3f1b5035726c0f7b9674744e72b0bb
Author: Noel Gordon <noel@chromium.org>
Date: Sat Aug 25 07:49:43 2018

Re-enable KeyboardOperations test renameNewFolderDownloads

Fix CL:1188178 landed. Re-enable renameNewFolderDownloads test.

Tbr: lucmult
Bug:  877557 
Change-Id: I45ccfa03001f1622aab4fd07abde224ccef45ef0
Reviewed-on: https://chromium-review.googlesource.com/1189322
Reviewed-by: Noel Gordon <noel@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#586128}
[modify] https://crrev.com/3ce1fba20a3f1b5035726c0f7b9674744e72b0bb/chrome/browser/chromeos/file_manager/file_manager_browsertest.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/26603d47dc649ae7ba318d8c55064534e2f8a2d5

commit 26603d47dc649ae7ba318d8c55064534e2f8a2d5
Author: Noel Gordon <noel@chromium.org>
Date: Mon Aug 27 01:22:44 2018

Deflake KeyboardOperations renameNewFolderDownloads test

Sending Enter to the file-list container after sending an Enter key to
the list renaming text input element causes flaky failures on the bots
due to [renaming] complete racing with the processing of the file-list
container Enter key handling.

To verify that the Folder cannot be entered while it is being renamed,
send Enter to the file-list container before sending Enter to the text
input [renaming] element.

Bug:  874954 , 877557 , 410163 
Change-Id: Icf8ec215b4a4658e16940ab8ce9b1778f19f6235
Reviewed-on: https://chromium-review.googlesource.com/1188726
Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#586180}
[modify] https://crrev.com/26603d47dc649ae7ba318d8c55064534e2f8a2d5/chrome/browser/chromeos/file_manager/file_manager_browsertest.cc
[modify] https://crrev.com/26603d47dc649ae7ba318d8c55064534e2f8a2d5/ui/file_manager/integration_tests/file_manager/keyboard_operations.js

Will use this bug to go over the remaining keyboard_operations.js code and bring it up to date, while we await results from #6.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/cf3c7c9eddb0ff6df44a009fa6e3cc7a15228fdb

commit cf3c7c9eddb0ff6df44a009fa6e3cc7a15228fdb
Author: Noel Gordon <noel@chromium.org>
Date: Mon Aug 27 05:05:25 2018

More KeyboardOperations test modernization

 waitAndAcceptDialog
  - document all steps herein, use appId.

 getTreeItems => getVisibleDirectoryTreeItemNames
  - name it by what is actually does, use appId.

 waitForDirectoryTreeItem, waitForDirectoryTreeItemLost
  - include directory in their names, use appId.

 keyboardCopy
  - remove unused |callback| argument, use appId.

 keyboardDeleteFolder
  - remove "directory" from the name to minimize
    the folder/directory naming dichotomy.

 testRenameFolder
  - use waitForElement in a consistent way.

Bug:  877557 
Change-Id: I8e9bd30bf98743764a0a4d7b9652a4854a52ee13
Reviewed-on: https://chromium-review.googlesource.com/1189512
Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#586194}
[modify] https://crrev.com/cf3c7c9eddb0ff6df44a009fa6e3cc7a15228fdb/ui/file_manager/integration_tests/file_manager/keyboard_operations.js

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/00dda8132b55a7e9762942ee65a2aed56766fb06

commit 00dda8132b55a7e9762942ee65a2aed56766fb06
Author: Noel Gordon <noel@chromium.org>
Date: Mon Aug 27 07:21:35 2018

Update KeyboardOperations test renameFile helper

Use appId, document all test steps, use precise selectors when dealing
with the #file-list [renaming] element and its <input> (exactly as per
the testRenameFolder test below), check step return results.

Bug:  877557 
Change-Id: If57085de229f8213852d0fd1730871a5ad059004
Reviewed-on: https://chromium-review.googlesource.com/1189516
Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#586200}
[modify] https://crrev.com/00dda8132b55a7e9762942ee65a2aed56766fb06/ui/file_manager/integration_tests/file_manager/keyboard_operations.js

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/65896a1f085a780db3cc8398b51d214daeb8294f

commit 65896a1f085a780db3cc8398b51d214daeb8294f
Author: Noel Gordon <noel@chromium.org>
Date: Mon Aug 27 07:26:27 2018

Write keyboardDeleteFolder test in terms of promises

Most tests herein are promise-based. Having a few tests in StepsRunner
is not great. Let promises win in this file.

Bug:  877557 
Change-Id: Idc075946864b89a17f0e6b887323dbae361e5564
Reviewed-on: https://chromium-review.googlesource.com/1189266
Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#586202}
[modify] https://crrev.com/65896a1f085a780db3cc8398b51d214daeb8294f/ui/file_manager/integration_tests/file_manager/keyboard_operations.js

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e3b048494a8412ea7e4cee4115c2ffc5f415e31b

commit e3b048494a8412ea7e4cee4115c2ffc5f415e31b
Author: Noel Gordon <noel@chromium.org>
Date: Mon Aug 27 07:34:33 2018

Speed-up and simplify KeyboardOperations testRenameFile test

Load only the file needed for the test (for speed and simplicity), use
appId, document each test step.

Bug:  877557 
Change-Id: I70a82b5334047587c5b426639347bf42c33d391d
Reviewed-on: https://chromium-review.googlesource.com/1188734
Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#586205}
[modify] https://crrev.com/e3b048494a8412ea7e4cee4115c2ffc5f415e31b/ui/file_manager/integration_tests/file_manager/keyboard_operations.js

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/10c61f03ec4352fd1aaef4fe6bc41d62e076acba

commit 10c61f03ec4352fd1aaef4fe6bc41d62e076acba
Author: Noel Gordon <noel@chromium.org>
Date: Mon Aug 27 07:58:23 2018

Write keyboardDelete test in terms of promises

Most tests herein are promise-based. Having a few tests in StepsRunner
is not great. Let promises win in this file.

Bug:  877557 
Change-Id: I0f778870684d3e55f038c1a5317f5c86983e747c
Reviewed-on: https://chromium-review.googlesource.com/1189269
Commit-Queue: Noel Gordon <noel@chromium.org>
Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Cr-Commit-Position: refs/heads/master@{#586209}
[modify] https://crrev.com/10c61f03ec4352fd1aaef4fe6bc41d62e076acba/ui/file_manager/integration_tests/file_manager/keyboard_operations.js

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3583dc2109bf865901310a06af4d700ba9d03a52

commit 3583dc2109bf865901310a06af4d700ba9d03a52
Author: Noel Gordon <noel@chromium.org>
Date: Mon Aug 27 10:21:03 2018

Write keyboardCopy test in terms of promises

Most tests herein are promise-based. Having a few tests in StepsRunner
is not great. Let promises win in this file.

Bug:  877557 
Change-Id: Ia063d4218e4e1c27957beac2fa3f850532eb4f64
Reviewed-on: https://chromium-review.googlesource.com/1189586
Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#586223}
[modify] https://crrev.com/3583dc2109bf865901310a06af4d700ba9d03a52/ui/file_manager/integration_tests/file_manager/keyboard_operations.js

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8a877845e123b56d331c2f77b2c81f51d5b16fe1

commit 8a877845e123b56d331c2f77b2c81f51d5b16fe1
Author: Noel Gordon <noel@chromium.org>
Date: Tue Aug 28 00:32:49 2018

KeyboardOperations testRenameFolder: change windowId to appId

Last use of windowId in this file. Make it |appId| for consistency. No
change in behavior, no new tests.

Test: browser_tests --gtest-filter="KeyboardOperations/FilesApp*"
Bug:  877557 
Change-Id: I3b829780c7c3b67d591a36ff4e15334307c33c9a
Reviewed-on: https://chromium-review.googlesource.com/1190042
Commit-Queue: Luciano Pacheco <lucmult@chromium.org>
Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Cr-Commit-Position: refs/heads/master@{#586520}
[modify] https://crrev.com/8a877845e123b56d331c2f77b2c81f51d5b16fe1/ui/file_manager/integration_tests/file_manager/keyboard_operations.js

renameNewFolderDownloads is not flaking anymore ...

Deleted: renameNewFolderDownloads.png 182 KB

	renameNewFolderDownloads.png 182 KB View Download

Link for reference:

https://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=keyboardOperations%2FFilesApp