Failure log:

[ RUN      ] QuickView/FileManagerBrowserTest.Test/2
[1693:1693:1228/154557.885388:WARNING:gpu_info.cc(104)] No active GPU found, returning primary GPU.
[1493:1658:1228/154557.958653:WARNING:child_process_launcher_helper_posix.cc(118)] Ignoring invalid file v8_context_snapshot.bin
[1493:1658:1228/154558.116188:WARNING:child_process_launcher_helper_posix.cc(118)] Ignoring invalid file v8_context_snapshot.bin
[1493:1658:1228/154558.178751:WARNING:child_process_launcher_helper_posix.cc(118)] Ignoring invalid file v8_context_snapshot.bin
[1493:1493:1228/154558.245993:ERROR:wallpaper_controller.cc(1189)] User is ephemeral or guest! Fallback to default wallpaper.
[1493:1658:1228/154558.261078:WARNING:child_process_launcher_helper_posix.cc(118)] Ignoring invalid file v8_context_snapshot.bin
[1493:1658:1228/154558.303877:WARNING:child_process_launcher_helper_posix.cc(118)] Ignoring invalid file v8_context_snapshot.bin
[1493:1658:1228/154558.432004:WARNING:child_process_launcher_helper_posix.cc(118)] Ignoring invalid file v8_context_snapshot.bin
[1493:1658:1228/154558.493303:WARNING:child_process_launcher_helper_posix.cc(118)] Ignoring invalid file v8_context_snapshot.bin
[1493:1658:1228/154558.509649:WARNING:child_process_launcher_helper_posix.cc(118)] Ignoring invalid file v8_context_snapshot.bin
[1493:1658:1228/154558.519029:WARNING:child_process_launcher_helper_posix.cc(118)] Ignoring invalid file v8_context_snapshot.bin
[1493:1658:1228/154558.547277:WARNING:child_process_launcher_helper_posix.cc(118)] Ignoring invalid file v8_context_snapshot.bin
[1493:1658:1228/154558.575918:WARNING:child_process_launcher_helper_posix.cc(118)] Ignoring invalid file v8_context_snapshot.bin
[1493:1658:1228/154558.602154:WARNING:child_process_launcher_helper_posix.cc(118)] Ignoring invalid file v8_context_snapshot.bin
[1493:1658:1228/154558.619752:WARNING:child_process_launcher_helper_posix.cc(118)] Ignoring invalid file v8_context_snapshot.bin
[1493:1658:1228/154558.652037:WARNING:child_process_launcher_helper_posix.cc(118)] Ignoring invalid file v8_context_snapshot.bin
[1493:1658:1228/154558.662914:WARNING:child_process_launcher_helper_posix.cc(118)] Ignoring invalid file v8_context_snapshot.bin
[1493:1658:1228/154558.715717:WARNING:child_process_launcher_helper_posix.cc(118)] Ignoring invalid file v8_context_snapshot.bin
[1493:1658:1228/154559.046972:WARNING:child_process_launcher_helper_posix.cc(118)] Ignoring invalid file v8_context_snapshot.bin
[1493:1493:1228/154600.160723:INFO:CONSOLE(4953)] "Requesting volume list.", source: chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/background/js/background_common_scripts.js (4953)
[1493:1493:1228/154600.182806:INFO:CONSOLE(4955)] "Volume list fetched with: 2 items.", source: chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/background/js/background_common_scripts.js (4955)
[1493:1493:1228/154600.182958:INFO:CONSOLE(4965)] "Initializing volume: downloads:Downloads", source: chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/background/js/background_common_scripts.js (4965)
[1493:1493:1228/154600.183702:INFO:CONSOLE(5368)] "Requesting file system.", source: chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/background/js/background_common_scripts.js (5368)
[1493:1493:1228/154600.201488:INFO:CONSOLE(4965)] "Initializing volume: drive:drive-user", source: chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/background/js/background_common_scripts.js (4965)
[1493:1493:1228/154600.201646:INFO:CONSOLE(5368)] "Requesting file system.", source: chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/background/js/background_common_scripts.js (5368)
[1493:1493:1228/154600.224161:INFO:CONSOLE(5416)] "File system obtained: downloads:Downloads", source: chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/background/js/background_common_scripts.js (5416)
[1493:1493:1228/154600.230090:INFO:CONSOLE(4969)] "Initialized volume: downloads:Downloads", source: chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/background/js/background_common_scripts.js (4969)
[1493:1493:1228/154600.231106:INFO:CONSOLE(5416)] "File system obtained: drive:drive-user", source: chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/background/js/background_common_scripts.js (5416)
[1493:1493:1228/154600.233581:INFO:CONSOLE(1164)] "Cache database creating or upgrading.", source: chrome-extension://pmfjbimdmchhbnneeidfognadeopoehp/background_scripts.js (1164)
[1493:1493:1228/154600.237451:INFO:CONSOLE(4969)] "Initialized volume: drive:drive-user", source: chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/background/js/background_common_scripts.js (4969)
[1493:1493:1228/154600.237588:INFO:CONSOLE(4973)] "Initialized all volumes.", source: chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/background/js/background_common_scripts.js (4973)
[1493:1493:1228/154600.287724:INFO:CONSOLE(4284)] "Waiting for the result of openMainWindow", source: chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/background/js/background_common_scripts.js (4284)
[1,2428483456:23:46:00.338331] Native Client module will be loaded at base address 0x00007e0200000000
[1493:1493:1228/154600.392568:INFO:CONSOLE(4281)] "Received the result of openMainWindow", source: chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/background/js/background_common_scripts.js (4281)
[1493:1493:1228/154600.614803:INFO:CONSOLE(0)] "Styling master document from stylesheets defined in HTML Imports is deprecated, and is planned to be removed in M65, around March 2018. Please refer to https://goo.gl/EGXzpw for possible migration paths.", source:  (0)
[1493:1658:1228/154602.996853:WARNING:child_process_launcher_helper_posix.cc(118)] Ignoring invalid file v8_context_snapshot.bin
ALSA lib confmisc.c:768:(parse_card) cannot find card '0'
ALSA lib conf.c:4248:(_snd_config_evaluate) function snd_func_card_driver returned error: No such file or directory
ALSA lib confmisc.c:392:(snd_func_concat) error evaluating strings
ALSA lib conf.c:4248:(_snd_config_evaluate) function snd_func_concat returned error: No such file or directory
ALSA lib confmisc.c:1251:(snd_func_refer) error evaluating name
ALSA lib conf.c:4248:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
ALSA lib conf.c:4727:(snd_config_expand) Evaluate error: No such file or directory
ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM default
[1493:1663:1228/154603.009421:WARNING:alsa_util.cc(24)] PcmOpen: default,No such file or directory
ALSA lib confmisc.c:768:(parse_card) cannot find card '0'
ALSA lib conf.c:4248:(_snd_config_evaluate) function snd_func_card_driver returned error: No such file or directory
ALSA lib confmisc.c:392:(snd_func_concat) error evaluating strings
ALSA lib conf.c:4248:(_snd_config_evaluate) function snd_func_concat returned error: No such file or directory
ALSA lib confmisc.c:1251:(snd_func_refer) error evaluating name
ALSA lib conf.c:4248:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
ALSA lib conf.c:4727:(snd_config_expand) Evaluate error: No such file or directory
ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM default
[1493:1663:1228/154603.009646:WARNING:alsa_util.cc(24)] PcmOpen: plug:default,No such file or directory
[1493:1663:1228/154603.009708:ERROR:audio_output_resampler.cc(396)] Unable to open audio device in high latency mode.  Falling back to fake audio output.
[1,2428483456:23:46:03.592034] Native Client module will be loaded at base address 0x0000407700000000
[1,2428483456:23:46:03.735938] Native Client module will be loaded at base address 0x0000722b00000000
[1493:1658:1228/154603.810449:WARNING:child_process_launcher_helper_posix.cc(118)] Ignoring invalid file v8_context_snapshot.bin
[1493:1493:1228/154604.040590:INFO:CONSOLE(71)] "Uncaught TypeError: Cannot read property 'contentWindow' of null", source: chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/foreground/elements/files_safe_media.js (71)
[1493:1493:1228/154604.223200:INFO:CONSOLE(0)] "[FAIL] openQuickViewForFoldersAfterClose: API Test Error in openQuickViewForFoldersAfterClose: The error count is not 0.
Actual: 1
Expected: 0
Error
    at Object.handleRequest (extensions::binding:64:27)
    at Object.<anonymous> (extensions::binding:374:32)
    at Object.<anonymous> (extensions::test:230:18)
    at Object.handleRequest (extensions::binding:64:27)
    at Object.<anonymous> (extensions::binding:374:32)
    at chrome-extension://oobinhbdbiehknkpbpejbbpdbkdjmoco/test_util.js:36:17", source: chrome-extension://oobinhbdbiehknkpbpejbbpdbkdjmoco/_generated_background_page.html (0)
[1493:1493:1228/154604.228116:INFO:CONSOLE(0)] "Uncaught (in promise) chrome.test.failure", source: chrome-extension://oobinhbdbiehknkpbpejbbpdbkdjmoco/_generated_background_page.html (0)
../../chrome/browser/chromeos/file_manager/file_manager_browsertest_base.cc:599: Failure
Failed
Failed 1 of 1 tests
[1493:1663:1228/154604.312115:WARNING:audio_sync_reader.cc(177)] ASR: No room in socket buffer.: Broken pipe (32)
[1493:1493:1228/154604.346747:ERROR:frame_sink_provider_impl.cc(34)] No RenderWidgetHost exists with id 3 in process 6
[1493:1493:1228/154604.417926:WARNING:event_router.cc(423)] Not all file watchers are removed. This can happen when the Files app is open during shutdown.
[1493:1493:1228/154604.418435:INFO:chrome_cryptauth_service.cc(233)] Profile is not authenticated yet; waiting before starting CryptAuth managers.
[1493:1493:1228/154604.448141:WARNING:url_request_context_getter.cc(43)] URLRequestContextGetter leaking due to no owning thread.
[  FAILED  ] QuickView/FileManagerBrowserTest.Test/2, where GetParam() = (0, 0x9a116f1 pointing to "openQuickViewForFoldersAfterClose") (7714 ms)

Yes, indeed https://crrev.com/c/856378 seems like a culprit. The CL says it
fixes the flakiness but it seems not.

testui, fukino: Do you agree with reverting the CL?

yutak@:
I agree to revert this as this is low impact.

fukino@:
However, this is very weird as L71 seems to be checking whether webview_ is null but #1 still says "Cannot read property 'contentWindow' of null".

https://cs.chromium.org/chromium/src/ui/file_manager/file_manager/foreground/elements/files_safe_media.js?l=71&rcl=d9a71c341af98d201c3c2cafc12f47612444db76

OK, so I'm trying to revert this now.

This is reverted as of
https://chromium.googlesource.com/chromium/src/+/d532b44ae1f17234429c8d653fd5cca2a253b0e6

Now I'm moving this off of sheriff queue, and leave this bug to you. (Feel free
to close if you don't need this bug to track the flakiness.)

 Issue 798772  has been merged into this issue.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/32c3b9ad1650af9935f282384790ae57df4b7cba

commit 32c3b9ad1650af9935f282384790ae57df4b7cba
Author: Noel Gordon <noel@chromium.org>
Date: Mon May 14 10:18:06 2018

Remove QuickView openQuickViewForFoldersAfterClose test

QuickView/FileManagerBrowserTest/Test0,1,2 (3 tests). The tests do the
following:

  Test/0 open QuickView
  Test/1 open then close QuickView
  Test/2 open then close then open QuickView again

The first two tests have run-time that is already near bot time limits
so Test/2 trying to open QuickView again will likely exceed bot limits
regularly and FAIL even in RELEASE. Remove this test.

Bug: 836254, 808745 
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: Icb91410cd095a305e1d9b189e5139c49c22cd39c
Reviewed-on: https://chromium-review.googlesource.com/1055911
Reviewed-by: Naoki Fukino <fukino@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#558247}
[modify] https://crrev.com/32c3b9ad1650af9935f282384790ae57df4b7cba/chrome/browser/chromeos/file_manager/file_manager_browsertest.cc
[modify] https://crrev.com/32c3b9ad1650af9935f282384790ae57df4b7cba/ui/file_manager/integration_tests/file_manager/quick_view.js