Findit identified the culprit r551288 with confidence 70.0% in the config "chromium.chromiumos / linux-chromeos-rel"
based on the flakiness trend:

https://findit-for-me.appspot.com/waterfall/flake?key=ag9zfmZpbmRpdC1mb3ItbWVypAELEhdNYXN0ZXJGbGFrZUFuYWx5c2lzUm9vdCJuY2hyb21pdW0uY2hyb21pdW1vcy9saW51eC1jaHJvbWVvcy1yZWwvNjk4Ny9icm93c2VyX3Rlc3RzL1JYWmxiblJ6UVhCcFZHVnpkQzVPWlhkc2VVbHVkSEp2WkhWalpXUk1hWE4wWlc1bGNnPT0MCxITTWFzdGVyRmxha2VBbmFseXNpcxgBDA


Automatically posted by the findit-for-me app (https://goo.gl/Ot9f7N).
Flake Analyzer is in beta.
Feedback is welcome! Please use component Tools>Test>FindIt>Flakiness

That CL modified a different test, it couldn't have caused flakiness in this one. Also looking at the graph, it doesn't look like there's any culprit in this range.

Can we disable EventsApiTest.NewlyIntroducedListener in the meanwhile?

Looking on https://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=EventsApiTest.NewlyIntroducedListener - I don't see any flakes on Mac.

All the flakes are timeouts, @comment4 ya we can disable non-mac then

Going to paste the logs from one of the failures for the record (though it doesn't say much)
https://logs.chromium.org/v/?s=chromium%2Fbb%2Fchromium.swarm%2FLinux_Swarm%2F83640%2F%2B%2Frecipes%2Fsteps%2Fbrowser_tests_on_Ubuntu%2F0%2Fstdout

[ RUN      ] EventsApiTest.NewlyIntroducedListener
Xlib:  extension "RANDR" missing on display ":99".
[19676:19754:0423/151203.992278:ERROR:bus.cc(394)] Failed to connect to the bus: Could not parse server address: Unknown address type (examples of valid types are "tcp" and on UNIX "unix")
[19676:19676:0423/151204.000006:WARNING:password_store_factory.cc(240)] Using basic (unencrypted) store for password storage. See https://chromium.googlesource.com/chromium/src/+/master/docs/linux_password_storage.md for more information about password storage options.
(browser_tests:19676): LIBDBUSMENU-GLIB-WARNING **: Unable to get session bus: Unknown or unsupported transport 'disabled' for address 'disabled:'
BrowserTestBase received signal: Terminated. Backtrace:
#0 0x0000049a391c base::debug::StackTrace::StackTrace()
#1 0x000004dfb745 content::(anonymous namespace)::DumpStackTraceSignalHandler()
#2 0x7f838a313cb0 <unknown>
#3 0x7f838a3cdc9d __poll
#4 0x7f838f65bfe4 <unknown>
#5 0x7f838f65c0ec g_main_context_iteration
#6 0x000004930362 base::MessagePumpGlib::Run()
#7 0x00000494d605 base::RunLoop::Run()
#8 0x000004e1bcaf content::RunThisRunLoop()
#9 0x000008bbe44e extensions::ResultCatcher::GetNextResult()
#10 0x00000290734e extensions::EventsApiTest_NewlyIntroducedListener_Test::RunTestOnMainThread()
#11 0x000004dfb46a content::BrowserTestBase::ProxyRunTestOnMainThreadLoop()
#12 0x000004a33233 ChromeBrowserMainParts::PreMainMessageLoopRunImpl()
#13 0x000004a31f9a ChromeBrowserMainParts::PreMainMessageLoopRun()
#14 0x000003883e41 content::BrowserMainLoop::PreMainMessageLoopRun()
#15 0x000003bb4c77 content::StartupTaskRunner::RunAllTasksNow()
#16 0x000003882a02 content::BrowserMainLoop::CreateStartupTasks()
#17 0x0000038866a3 content::BrowserMainRunnerImpl::Initialize()
#18 0x000003880624 content::BrowserMain()
#19 0x0000048d74e8 content::ContentMainRunnerImpl::Run()
#20 0x0000061f74f4 service_manager::Main()
#21 0x0000048d5634 content::ContentMain()
#22 0x000004dfb04c content::BrowserTestBase::SetUp()
#23 0x0000049da1e9 InProcessBrowserTest::SetUp()
#24 0x000002ffe0ed testing::Test::Run()
#25 0x000002ffed10 testing::TestInfo::Run()
#26 0x000002fff217 testing::TestCase::Run()
#27 0x00000300ab37 testing::internal::UnitTestImpl::RunAllTests()
#28 0x00000300a6be testing::UnitTest::Run()
#29 0x0000049eb782 base::TestSuite::Run()
#30 0x00000490e952 ChromeTestSuiteRunner::RunTestSuite()
#31 0x000004e1872f content::LaunchTests()
#32 0x00000490edf4 LaunchChromeTests()
#33 0x00000490e8de main
#34 0x7f838a2fef45 __libc_start_main
#35 0x000001be202a _start
[2241/4327] EventsApiTest.NewlyIntroducedListener (TIMED OUT)

Great. Landing https://chromium-review.googlesource.com/c/chromium/src/+/1025138 then.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/80f017b298b6dfe653f3932ec406b2075a21e742

commit 80f017b298b6dfe653f3932ec406b2075a21e742
Author: Lei Zhang <thestig@chromium.org>
Date: Mon Apr 23 23:18:02 2018

Disable EventsApiTest.NewlyIntroducedListener on non-Mac.

The test randomly times out.

BUG=833854
TBR=yoichio@chromium.org
NOTRY=true

Change-Id: Iffd451c87381c6d6520fd8ba8ba51beeadd2e30c
Reviewed-on: https://chromium-review.googlesource.com/1025138
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#552884}
[modify] https://crrev.com/80f017b298b6dfe653f3932ec406b2075a21e742/chrome/browser/extensions/events_apitest.cc