Chrome Version: 65.0.3311.0
OS: Chrome

QuickView/FileManagerBrowserTest in browser_tests has been occasionally flaky since at least 12/07/17.  See for example:
  https://ci.chromium.org/buildbot/chromium.chromiumos/linux-chromeos-dbg/3060
  https://ci.chromium.org/buildbot/chromium.chromiumos/linux-chromeos-dbg/3499
  https://ci.chromium.org/buildbot/chromium.chromiumos/linux-chromeos-dbg/3542

Final try from that last run:

Retrying 1 test (retry #3)
Still waiting for the following processes to finish:
	./browser_tests --brave-new-test-launcher --cfi-diag=0 --gtest_also_run_disabled_tests --gtest_filter=QuickView/FileManagerBrowserTest.Test/2 --single_process --test-launcher-bot-mode --test-launcher-output=/b/s/w/it1Im2xu/.org.chromium.Chromium.bWOOmQ/resultsY39P1K/test_results.xml --test-launcher-summary-output=/b/s/w/ioepd3Wb/output.json --user-data-dir=/b/s/w/it1Im2xu/.org.chromium.Chromium.bWOOmQ/dJCXa27
[0103/034247.690114:ERROR:kill_posix.cc(84)] Unable to terminate process group 29091: No such process (3)
[ RUN      ] QuickView/FileManagerBrowserTest.Test/2
    ...
[29091:29091:0103/034245.928500:INFO:CONSOLE(71)] "Uncaught TypeError: Cannot read property 'contentWindow' of null", source: chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj/foreground/elements/files_safe_media.js (71)
[29091:29091:0103/034246.503364: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)
[29091:29091:0103/034246.503983: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
[29091:29091:0103/034247.228298:WARNING:event_router.cc(423)] Not all file watchers are removed. This can happen when the Files app is open during shutdown.
[29091:29091:0103/034247.230434:INFO:chrome_cryptauth_service.cc(233)] Profile is not authenticated yet; waiting before starting CryptAuth managers.
[29091:29091:0103/034247.427670:WARNING:url_request_context_getter.cc(43)] URLRequestContextGetter leaking due to no owning thread.
[  FAILED  ] QuickView/FileManagerBrowserTest.Test/2, where GetParam() = (0, 0xca3ce97 pointing to "openQuickViewForFoldersAfterClose") (16442 ms)
[457/457] QuickView/FileManagerBrowserTest.Test/2 (17831 ms)
1 test failed:
    QuickView/FileManagerBrowserTest.Test/2 (../../chrome/browser/chromeos/file_manager/file_manager_browsertest.cc:40)

+tetsui@, would you mind taking a look or triaging this, since you took care of the last time this test flaked ( Issue 668142 )?