Logs from https://chromium-swarm.appspot.com/task?id=41db494280720810&refresh=10&show_raw=1:

Additional test environment:
    CHROME_DEVEL_SANDBOX=/opt/chromium/chrome_sandbox
    CHROME_HEADLESS=1
    LANG=en_US.UTF-8
Command: C:\b\s\w\ir\.swarming_module_cache\vpython\9ff274\Scripts\python.exe ..\..\testing\scripts\run_isolated_script_test.py --isolated-script-test-output=C:\b\s\w\iowea_we\results.json ../../chrome/test/mini_installer/test_installer.py --output-dir=C:\b\s\w\iowea_we --isolated-script-test-output=C:\b\s\w\iowea_we\output.json --isolated-script-test-perf-output=C:\b\s\w\iowea_we\perftest-output.json

[1218/095938:test_installer.py(504)] Config found at C:\b\s\w\ir\chrome\test\mini_installer\config\config.config
[1218/095938:test_installer.py(542)] Setting --force-clean
ChromeUserLevel: no_pv -> install_chrome_user -> chrome_user_installed_not_inuse -> test_chrome_with_chromedriver_user -> chrome_user_installed_not_inuse -> uninstall_chrome_user -> clean
 ... [1218/095941:test_installer.py(190)] Verifying state no_pv
[1218/095941:test_installer.py(157)] Beginning action install_chrome_user
[1218/095946:test_installer.py(160)] Finished action install_chrome_user
[1218/095946:test_installer.py(190)] Verifying state chrome_user_installed_not_inuse
[1218/095946:test_installer.py(157)] Beginning action test_chrome_with_chromedriver_user
[1218/095950:test_installer.py(231)] stdout:
[1218/095950:test_chrome_with_chromedriver.py(85)] Saved Chrome crash dump to C:\b\s\w\iowea_we\7c4bc08f-3ffb-46df-a4cc-5559ed80a133.dmp
Traceback (most recent call last):
  File "test_chrome_with_chromedriver.py", line 182, in <module>
    sys.exit(main())
  File "test_chrome_with_chromedriver.py", line 177, in main
    'The page body was not correct')
  File "C:\b\s\w\ir\.swarming_module\bin\Lib\contextlib.py", line 24, in __exit__
    self.gen.next()
  File "test_chrome_with_chromedriver.py", line 129, in CreateChromedriver
    report_count)
Exception: Failing test due to 1 crash reports found
ERROR

https://chromium-review.googlesource.com/c/chromium/src/+/1384004 may help.

One crash I looked at is issue 916461. There may be others.

https://chromium-review.googlesource.com/c/chromium/src/+/1384025 removes the DCHECK described in issue 916461.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d5cf001c4db2cc46df12665af782e67df0db395b

commit d5cf001c4db2cc46df12665af782e67df0db395b
Author: Greg Thompson <grt@chromium.org>
Date: Wed Dec 19 20:05:39 2018

Include Chrome logs in the test output when crash reports are found.

It's possible that the logs will include information, such as a log
message or stack trace, from a failed [D]CHECK. This CL emits the Chrome
logs in the test output and copies them into the output directory in
case a crash report is found.

BUG=907979, 916389 

Change-Id: I5817d1f561259ee70e2b341be0d0fa7d92c9072d
Reviewed-on: https://chromium-review.googlesource.com/c/1384004
Reviewed-by: Roger Tawa <rogerta@chromium.org>
Commit-Queue: Greg Thompson <grt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#617920}
[modify] https://crrev.com/d5cf001c4db2cc46df12665af782e67df0db395b/chrome/test/mini_installer/test_chrome_with_chromedriver.py

__main__.InstallerTest.ChromeUserLevel is flaky.

Findit has detected 4 new flake occurrences of this test. List
of all flake occurrences can be found at:
https://findit-for-me.appspot.com/flake/occurrences?key=ag9zfmZpbmRpdC1mb3ItbWVyTwsSBUZsYWtlIkRjaHJvbWl1bUBtaW5pX2luc3RhbGxlcl90ZXN0c0BfX21haW5fXy5JbnN0YWxsZXJUZXN0LkNocm9tZVVzZXJMZXZlbAw.

Since these tests are still flaky, this issue has been moved back onto the Sheriff Bug Queue if it hasn't already.

If the result above is wrong, please file a bug using this link:
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%20Detection%20-%20Wrong%20result%3A%20__main__.InstallerTest.ChromeUserLevel&comment=Link%20to%20flake%20details%3A%20https://findit-for-me.appspot.com/flake/occurrences?key=ag9zfmZpbmRpdC1mb3ItbWVyTwsSBUZsYWtlIkRjaHJvbWl1bUBtaW5pX2luc3RhbGxlcl90ZXN0c0BfX21haW5fXy5JbnN0YWxsZXJUZXN0LkNocm9tZVVzZXJMZXZlbAw

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

[Sheriff] Removing label Sheriff-Chromium as grt@ is investigating.

__main__.InstallerTest.ChromeUserLevel is flaky.

Findit has detected 4 new flake occurrences of this test. List
of all flake occurrences can be found at:
https://findit-for-me.appspot.com/flake/occurrences?key=ag9zfmZpbmRpdC1mb3ItbWVyTwsSBUZsYWtlIkRjaHJvbWl1bUBtaW5pX2luc3RhbGxlcl90ZXN0c0BfX21haW5fXy5JbnN0YWxsZXJUZXN0LkNocm9tZVVzZXJMZXZlbAw.

Since these tests are still flaky, this issue has been moved back onto the Sheriff Bug Queue if it hasn't already.

If the result above is wrong, please file a bug using this link:
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%20Detection%20-%20Wrong%20result%3A%20__main__.InstallerTest.ChromeUserLevel&comment=Link%20to%20flake%20details%3A%20https://findit-for-me.appspot.com/flake/occurrences?key=ag9zfmZpbmRpdC1mb3ItbWVyTwsSBUZsYWtlIkRjaHJvbWl1bUBtaW5pX2luc3RhbGxlcl90ZXN0c0BfX21haW5fXy5JbnN0YWxsZXJUZXN0LkNocm9tZVVzZXJMZXZlbAw

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

Issue 917051 has been merged into this issue.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a8f33aee59bc7840fedcd7e169acb487ed75da7b

commit a8f33aee59bc7840fedcd7e169acb487ed75da7b
Author: Greg Thompson <grt@chromium.org>
Date: Fri Dec 21 15:53:26 2018

Remove DCHECK on CreateTrialsFromSwitchValue failures.

This DCHECK is hit in utility processes during test_installer
runs. The attempt to duplicate the parent proc's handle in
DeserializeSharedMemoryHandleMetadata fails because the browser
process is being torn down.

BUG= 916389 ,916461
R=asvitkine@chromium.org

Change-Id: I27c03717c0272bdf309f78e0a1724d7d0f205c57
Reviewed-on: https://chromium-review.googlesource.com/c/1384025
Commit-Queue: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#618539}
[modify] https://crrev.com/a8f33aee59bc7840fedcd7e169acb487ed75da7b/base/metrics/field_trial.cc

Flakes have stopped for now. Issue 917051 tracks making the test harness retry so that flakes have less impact on cycle time.