Flaked for me in https://ci.chromium.org/buildbot/tryserver.chromium.chromiumos/linux-chromeos-rel/85390
chromevox_tests failed 39 times in last 200 builds.

[ RUN      ] BackgroundTest.ActiveDescendantUpdates
[2638:2638:0323/122331.592894:WARNING:chrome_browser_main_chromeos.cc(618)] Running as stub user with profile dir: test-user
[2638:2660:0323/122331.638952:ERROR:logging_chrome.cc(218)] Unable to create symlink /b/s/w/itMEJ5na/.org.chromium.Chromium.jAjrF2/dmPxBz4/test-user/chrome_debug.log pointing at /b/s/w/itMEJ5na/.org.chromium.Chromium.jAjrF2/dmPxBz4/test-user/chrome_debug_20180323-122331: No such file or directory (2)
[2638:2638:0323/122331.706766:WARNING:user_session_manager.cc(1068)] Attempting to save user password for non enterprise user.
[2638:2638:0323/122331.847273:ERROR:network_type_pattern.cc(134)] NetworkTypePattern: wifi: Can not match empty type.
[2638:2638:0323/122331.847641:ERROR:network_type_pattern.cc(134)] NetworkTypePattern: wifi: Can not match empty type.
[2638:2638:0323/122331.848028:ERROR:network_type_pattern.cc(134)] NetworkTypePattern: wifi: Can not match empty type.
[2638:2638:0323/122331.848627:ERROR:network_type_pattern.cc(134)] NetworkTypePattern: wifi: Can not match empty type.
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
[2638:2666:0323/122332.013424: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
[2638:2666:0323/122332.013608:WARNING:alsa_util.cc(24)] PcmOpen: plug:default,No such file or directory
[2638:2666:0323/122332.013689:ERROR:audio_output_resampler.cc(396)] Unable to open audio device in high latency mode.  Falling back to fake audio output.
[2638:2657:0323/122332.172914:WARNING:simple_synchronous_entry.cc(1255)] Could not open platform files for entry.
[2638:2638:0323/122332.681215:INFO:CONSOLE(946)] "Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check https://xhr.spec.whatwg.org/.", source: chrome-extension://mndnfokpggljbaajbnioimlmbfngpief/chromeVox2ChromeBackgroundScript.js (946)
[2638:2660:0323/122333.712290:ERROR:component_loader.cc(93)] Can't load /usr/share/chromeos-assets/speech_synthesis/patts/manifest.json: Manifest file is missing or unreadable
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
[2638:2666:0323/122333.746363: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
[2638:2666:0323/122333.746538:WARNING:alsa_util.cc(24)] PcmOpen: plug:default,No such file or directory
[2638:2666:0323/122333.746577:ERROR:audio_output_resampler.cc(396)] Unable to open audio device in high latency mode.  Falling back to fake audio output.
[1:24:0323/122333.747708:WARNING:PushPullFIFO.cpp(189)] PushPullFIFO: underflow while pulling (underflowCount=1, availableFrames=0, requestedFrames=441, fifoLength=12288)
[2638:2638:0323/122333.824968:INFO:CONSOLE(1121)] "Speak (C) category=nav "Address and search bar"", source: chrome-extension://mndnfokpggljbaajbnioimlmbfngpief/chromeVox2ChromeBackgroundScript.js (1121)
[2638:2638:0323/122333.825985:INFO:CONSOLE(1121)] "Speak (Q) category=nav "about:blank"", source: chrome-extension://mndnfokpggljbaajbnioimlmbfngpief/chromeVox2ChromeBackgroundScript.js (1121)
[2638:2638:0323/122333.826684:INFO:CONSOLE(1121)] "Speak (Q) category=nav "Edit text, URL entry"", source: chrome-extension://mndnfokpggljbaajbnioimlmbfngpief/chromeVox2ChromeBackgroundScript.js (1121)
[2638:2638:0323/122333.827979:INFO:CONSOLE(1121)] "Speak (Q) category=nav "about:blank - Chromium - Shadow, window"", source: chrome-extension://mndnfokpggljbaajbnioimlmbfngpief/chromeVox2ChromeBackgroundScript.js (1121)
[2638:2638:0323/122333.828892:INFO:CONSOLE(1121)] "Speak (Q) category=nav "Press up or down arrow for auto completions."", source: chrome-extension://mndnfokpggljbaajbnioimlmbfngpief/chromeVox2ChromeBackgroundScript.js (1121)
[2638:2638:0323/122333.829670:INFO:CONSOLE(1121)] "Speak (Q) category=nav "Type to auto complete."", source: chrome-extension://mndnfokpggljbaajbnioimlmbfngpief/chromeVox2ChromeBackgroundScript.js (1121)
[2638:2638:0323/122333.863273:INFO:CONSOLE(1121)] "Speak (Q) "ChromeVox spoken feedback is ready"", source: chrome-extension://mndnfokpggljbaajbnioimlmbfngpief/chromeVox2ChromeBackgroundScript.js (1121)
[2638:2638:0323/122333.897454:INFO:CONSOLE(7728)] "Running TestCase BackgroundTest.ActiveDescendantUpdates", source: file:///b/s/w/ir/out/Release/test_data/chrome/browser/resources/chromeos/chromevox/cvox2/background/background_test.extjs (7728)
[1,1628280704:19:23:33.998446] Native Client module will be loaded at base address 0x00003f6b00000000
[2638:2638:0323/122334.296779:INFO:CONSOLE(2029)] "ChromeVox waiting for background page: data:text/html,<!doctype html><div aria-label="container" tabindex=0 role="group" id="active" aria-activedescendant="1"> <div id="1" role="treeitem"></div> <div id="2" role="treeitem"></div> <script> var alt = false; var active = document.getElementById('active'); var one = document.getElementById('1'); var two = document.getElementById('2'); active.addEventListener('click', function() { var sel = alt ? one : two; var unsel = alt ? two : one; active.setAttribute('aria-activedescendant', sel.id); sel.setAttribute('aria-selected', true); unsel.setAttribute('aria-selected', false); alt = !alt; }); </script>. Will try again in 100ms", source: chrome-extension://mndnfokpggljbaajbnioimlmbfngpief/chromeVoxChromePageScript.js (2029)
[2638:2638:0323/122336.278278:INFO:CONSOLE(635)] "loaded liblouis Native Client instance", source: chrome-extension://mndnfokpggljbaajbnioimlmbfngpief/chromeVox2ChromeBackgroundScript.js (635)
[2638:2638:0323/122336.356261:INFO:CONSOLE(1788)] "Injecting into 2", source: chrome-extension://mndnfokpggljbaajbnioimlmbfngpief/chromeVox2ChromeBackgroundScript.js (1788)
[2638:2638:0323/122336.618044:INFO:CONSOLE(2029)] "ChromeVox waiting for background page: about:blank. Will try again in 100ms", source: chrome-extension://chromevox/chromeVoxChromePageScript.js (2029)
[2638:2638:0323/122338.233778:INFO:CONSOLE(9178)] "Still waiting for Speak 'Selected'", source: file:///b/s/w/ir/out/Release/test_data/chrome/browser/resources/chromeos/chromevox/cvox2/background/background_test.extjs (9178)
[2638:2638:0323/122338.233891:INFO:CONSOLE(9181)] "Pending speech utterances:
  ' 2 of 2 '
  ' level 2 '
  'Press Search+Space to toggle.'
  'container'
  'container'
  ", source: file:///b/s/w/ir/out/Release/test_data/chrome/browser/resources/chromeos/chromevox/cvox2/background/background_test.extjs (9181)
[2638:2638:0323/122338.233979:INFO:CONSOLE(9181)] "Pending braille:
  'tab created' startIndex=-1 endIndex=-1
  'Untitled - Chromium - Shadow, window' startIndex=-1 endIndex=-1
  'Untitled - Chromium - Shadow, window' startIndex=-1 endIndex=-1
  'data:text/html,<!doctype html><div aria-label="container" tabindex=0 role="group" id="active" aria-activedescendant="1"> <div id="1" role="treeitem"></div> <div id="2" role="treeitem"></div> <script> var alt = false; var active = document.getElementById('active'); var one = document.getElementById('1'); var two = document.getElementById('2'); active.addEventListener('click', function() { var sel = alt ? one : two; var unsel = alt ? two : one; active.setAttribute('aria-activedescendant', sel.id); sel.setAttribute('aria-selected', true); unsel.setAttribute('aria-selected', false); alt = !alt; }); </script>, tab' startIndex=-1 endIndex=-1
  'data:text/html,<!doctype html><div aria-label="container" tabindex=0 role="group" id="active" aria-activedescendant="1"> <div id="1" role="treeitem"></div> <div id="2" role="treeitem"></div> <script> var alt = false; var active = document.getElementById('active'); var one = document.getElementById('1'); var two = document.getElementById('2'); active.addEventListener('click', function() { var sel = alt ? one : two; var unsel = alt ? two : one; active.setAttribute('aria-activedescendant', sel.id); sel.setAttribute('aria-selected', true); unsel.setAttribute('aria-selected', false); alt = !alt; }); </script>' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'tritm 2/2 level 2 Press Search+Space to toggle.' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  'container' startIndex=-1 endIndex=-1
  ", source: file:///b/s/w/ir/out/Release/test_data/chrome/browser/resources/chromeos/chromevox/cvox2/background/background_test.extjs (9181)
[2638:2638:0323/122338.234086:INFO:CONSOLE(9181)] "Pending earcons:
  'object_open'
  'page_start_loading'
  'object_select'
  'page_finish_loading'
  'object_open'
  'object_open'
  ", source: file:///b/s/w/ir/out/Release/test_data/chrome/browser/resources/chromeos/chromevox/cvox2/background/background_test.extjs (9181)
BrowserTestBase received signal: Terminated. Backtrace:
#0 0x000002f3bbec base::debug::StackTrace::StackTrace()
#1 0x000003382f12 content::(anonymous namespace)::DumpStackTraceSignalHandler()
#2 0x7fa9f5ff2cb0 <unknown>
#3 0x7fa9f60ba693 epoll_wait
#4 0x0000033900ad epoll_dispatch
#5 0x00000338db9c event_base_loop
#6 0x000002f600e1 base::MessagePumpLibevent::Run()
#7 0x000002f5d3f9 base::MessageLoop::Run()
#8 0x000002f878b9 base::RunLoop::Run()
#9 0x000003389bf6 content::MessageLoopRunner::Run()
#10 0x000003384c43 content::DOMMessageQueue::WaitForMessage()
#11 0x000003384197 content::(anonymous namespace)::ExecuteScriptHelper()
#12 0x000003383fb2 content::ExecuteScriptAndExtractString()
#13 0x000002f31140 extensions::browsertest_util::ExecuteScriptInBackgroundPage()
#14 0x000000435424 ExtensionJSBrowserTest::RunJavascriptTestF()
#15 0x000000449f1a BackgroundTest_ActiveDescendantUpdates_Test::RunTestOnMainThread()
#16 0x000003382c6d content::BrowserTestBase::ProxyRunTestOnMainThreadLoop()
#17 0x000003026641 ChromeBrowserMainParts::PreMainMessageLoopRunImpl()
#18 0x00000302540a ChromeBrowserMainParts::PreMainMessageLoopRun()
#19 0x000001f27a81 chromeos::ChromeBrowserMainPartsChromeos::PreMainMessageLoopRun()
#20 0x0000013623d1 content::BrowserMainLoop::PreMainMessageLoopRun()
#21 0x0000017a6c35 content::StartupTaskRunner::RunAllTasksNow()
#22 0x000001360e52 content::BrowserMainLoop::CreateStartupTasks()
#23 0x000001364ec3 content::BrowserMainRunnerImpl::Initialize()
#24 0x00000135e7a2 content::BrowserMain()
#25 0x000002f1d8ed content::ContentMainRunnerImpl::Run()
#26 0x000004c04db3 service_manager::Main()
#27 0x000002f1bf14 content::ContentMain()
#28 0x0000033827fb content::BrowserTestBase::SetUp()
#29 0x000003380a11 InProcessBrowserTest::SetUp()
#30 0x00000068fec1 testing::Test::Run()
#31 0x0000006906e0 testing::TestInfo::Run()
#32 0x000000690bc7 testing::TestCase::Run()
#33 0x00000069c097 testing::internal::UnitTestImpl::RunAllTests()
#34 0x00000069bc1e testing::UnitTest::Run()
#35 0x00000300f182 base::TestSuite::Run()
#36 0x00000337fcb5 ChromeTestSuiteRunner::RunTestSuite()
#37 0x000003386557 content::LaunchTests()
#38 0x000003380174 LaunchChromeTests()
#39 0x00000337fc4e main
#40 0x7fa9f5fddf45 __libc_start_main
#41 0x000000432b4a _start
[98/470] BackgroundTest.ActiveDescendantUpdates (TIMED OUT)