Linking test CL that demonstrate failure on trybots:
https://chromium-review.googlesource.com/c/chromium/src/+/1183540

Dumping call stack

[ RUN      ] SSLUICaptivePortalListResourceBundleTest.Enabled/1
Xlib:  extension "RANDR" missing on display ":99".
[3664:3664:0821/091850.664322:ERROR:browser_dm_token_storage_linux.cc(93)] Error: /etc/machine-id contains 32 characters (32 were expected).
[3664:3701:0821/091850.753558: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")
[3664:3664:0821/091850.761686:WARNING:password_store_factory.cc(261)] 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:3664): LIBDBUSMENU-GLIB-WARNING **: Unable to get session bus: Unknown or unsupported transport 'disabled' for address 'disabled:'
[3699:3742:0821/091850.843575:WARNING:file_path_watcher_linux.cc(656)] Watch failed for /etc/../run/resolvconf: No such file or directory (2)
[3664:3664:0821/091850.868145:WARNING:gaia_auth_fetcher.cc(931)] Could not reach Google Accounts servers: errno -11
[3664:3664:0821/091850.907408:FATAL:thread_restrictions.cc(29)] Check failed: !g_blocking_disallowed.Get().Get(). Function marked as blocking was called from a scope that disallows blocking! If this task is running inside the TaskScheduler, it needs to have MayBlock() in its TaskTraits. Otherwise, consider making this blocking work asynchronous or, as a last resort, you may use ScopedAllowBlocking (see its documentation for best practices).
#0 0x00000640f2fc base::debug::StackTrace::StackTrace()
#1 0x00000635d12b logging::LogMessage::~LogMessage()
#2 0x0000063dfba6 base::AssertBlockingAllowed()
#3 0x000006acf6cf net::internal::AddressTrackerLinux::ReadMessages()
#4 0x000006acf2a1 net::internal::AddressTrackerLinux::Init()
#5 0x000006adf9a7 net::GetNetworkList()
#6 0x000006adfa9a net::GetWifiSSID()
#7 0x0000066d28e4 CaptivePortalBlockingPage::GetWiFiSSID()
#8 0x0000066d29f8 CaptivePortalBlockingPage::PopulateInterstitialStrings()
#9 0x000008ed2a5c security_interstitials::SecurityInterstitialPage::GetHTMLContents()
#10 0x0000066e6880 SSLErrorNavigationThrottle::ShowInterstitial()
#11 0x00000467534f _ZN4base8internal7InvokerINS0_9BindStateIMN6policy19URLBlacklistManagerEFvNSt3__110unique_ptrINS3_12URLBlacklistENS5_14default_deleteIS7_EEEEEJNS_7WeakPtrIS4_EEEEEFvSA_EE7RunImplISC_NS5_5tupleIJSE_EEEJLm0EEEEvOT_OT0_NS5_16integer_sequenceImJXspT1_EEEEOSA_
#12 0x0000066e251f (anonymous namespace)::SSLErrorHandlerDelegateImpl::ShowCaptivePortalInterstitial()
#13 0x0000066e089a SSLErrorHandler::StartHandlingError()
#14 0x0000066e0521 SSLErrorHandler::HandleSSLError()
#15 0x0000064dd333 _ZN4base8internal7InvokerINS0_9BindStateIPFvPN7content11WebContentsEiRKN3net7SSLInfoERK4GURLbNSt3__110unique_ptrI15SSLCertReporterNSD_14default_deleteISF_EEEERKNS_17RepeatingCallbackIFvNS3_28CertificateRequestResultTypeEEEENS_12OnceCallbackIFvNSE_IN22security_interstitials24SecurityInterstitialPageENSG_ISR_EEEEEEEEJEEESW_E3RunEPNS0_13BindStateBaseES5_iS9_SC_bOSI_SO_OSV_
#16 0x0000066e6afe _ZN4base8internal13FunctorTraitsINS_12OnceCallbackIFvPN7content11WebContentsEiRKN3net7SSLInfoERK4GURLbNSt3__110unique_ptrI15SSLCertReporterNSD_14default_deleteISF_EEEERKNS_17RepeatingCallbackIFvNS3_28CertificateRequestResultTypeEEEENS2_IFvNSE_IN22security_interstitials24SecurityInterstitialPageENSG_ISQ_EEEEEEEEEEvE6InvokeISW_JS5_iS7_SA_bSI_SM_SU_EEEvOT_DpOT0_
#17 0x0000066e698a _ZN4base8internal7InvokerINS0_9BindStateINS_12OnceCallbackIFvPN7content11WebContentsEiRKN3net7SSLInfoERK4GURLbNSt3__110unique_ptrI15SSLCertReporterNSE_14default_deleteISG_EEEERKNS_17RepeatingCallbackIFvNS4_28CertificateRequestResultTypeEEEENS3_IFvNSF_IN22security_interstitials24SecurityInterstitialPageENSH_ISR_EEEEEEEEEEJS6_iS8_SB_bSJ_SN_SV_EEEFvvEE7RunOnceEPNS0_13BindStateBaseE
#18 0x00000636799d base::debug::TaskAnnotator::RunTask()
#19 0x000006366916 base::MessageLoop::RunTask()
#20 0x000006366e22 base::MessageLoop::DoWork()
#21 0x00000636aa99 base::MessagePumpGlib::Run()
#22 0x0000063662e1 base::MessageLoop::Run()
#23 0x000006390aa6 base::RunLoop::Run()
#24 0x000006a4f1f0 content::MessageLoopRunner::Run()
#25 0x000006a4da56 content::TestNavigationObserver::Wait()
#26 0x00000645dc3d ui_test_utils::NavigateToURLWithDispositionBlockUntilNavigationsComplete()
#27 0x000002c28c49 SSLUICaptivePortalListResourceBundleTest_Enabled_Test::RunTestOnMainThread()
#28 0x000006a23a12 content::BrowserTestBase::ProxyRunTestOnMainThreadLoop()
#29 0x0000064c142e ChromeBrowserMainParts::PreMainMessageLoopRunImpl()
#30 0x0000064c003a ChromeBrowserMainParts::PreMainMessageLoopRun()
#31 0x00000485a701 content::BrowserMainLoop::PreMainMessageLoopRun()
#32 0x000004d41435 content::StartupTaskRunner::RunAllTasksNow()
#33 0x000004858c09 content::BrowserMainLoop::CreateStartupTasks()
#34 0x00000485d593 content::BrowserMainRunnerImpl::Initialize()
#35 0x0000048564c2 content::BrowserMain()
#36 0x0000062b78b8 content::ContentMainRunnerImpl::Run()
#37 0x00000852fbb9 service_manager::Main()
#38 0x0000062b5ac1 content::ContentMain()
#39 0x000006a2356e content::BrowserTestBase::SetUp()
#40 0x000006458c62 InProcessBrowserTest::SetUp()
#41 0x0000039dee8d testing::Test::Run()
#42 0x0000039dfaf0 testing::TestInfo::Run()
#43 0x0000039e0007 testing::TestCase::Run()
#44 0x0000039eb8b7 testing::internal::UnitTestImpl::RunAllTests()
#45 0x0000039eb42d testing::UnitTest::Run()
#46 0x0000064714c1 base::TestSuite::Run()
#47 0x00000633a102 ChromeTestSuiteRunner::RunTestSuite()
#48 0x000006a4a915 content::LaunchTests()
#49 0x00000633a5a3 LaunchChromeTests()
#50 0x00000633a08e main
#51 0x7fa532558f45 __libc_start_main
#52 0x00000249c02a _start
[622/622] SSLUICaptivePortalListResourceBundleTest.Enabled/1 (CRASHED)

Same issue as bug 817151?

Seems like it.