https://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_chromeos_ozone_rel_ng/builds/358172

Stacks are a little mangled:
m number of clients reachedui::X11EventSource::X11EventSource()
#8 0x000002e5bd1d ui::X11EventSource::X11EventSource()
#8 0x000002e5bd1d gpu::GpuInit::InitializeAndStartSandbox()
#11 0x0000049189c9 ui::X11EventSourceLibevent::X11EventSourceLibevent()
#9 0x000000cbc570 ui::(anonymous namespace)::OzonePlatformX11::InitializeGPU()
#10 0x000002ec2919 gpu::GpuInit::InitializeAndStartSandbox()
#11 0x0000049189c9 Maximum number of clients reached[2329:2329:0409/091831.344608:40450844876:FATAL:x11_event_source.cc(106)] Check failed: display_.
#0 0x00000238de37 base::debug::StackTrace::StackTrace()
#1 0x0000023a034a logging::LogMessage::~LogMessage()
#2 0x000002e5cb81 ui::X11EventSource::X11EventSource()
#3 0x000002e5bd1d ui::X11EventSourceLibevent::X11EventSourceLibevent()
#4 0x000000cbc570 ui::(anonymous namespace)::OzonePlatformX11::InitializeGPU()
#5 0x000002ec2919 gpu::GpuInit::InitializeAndStartSandbox()
#6 0x0000049189c9 content::GpuMain()
#7 0x00000189444c content::ContentMainRunnerImpl::Run()
#8 0x00000347683f service_manager::Main()
#9 0x000000e3c262 content::ContentMain()
#10 0x000001f3008d content::LaunchTests()
#11 0x000001f161b3 main
#12 0x7f5ff92d7f45 __libc_start_main
#13 0x0000004a59c2 <unknown>

BrowserTestBase received signal: Terminated. Backtrace:
#0 0x00000238de37 base::debug::StackTrace::StackTrace()
#1 0x000001f1b7a6 content::(anonymous namespace)::DumpStackTraceSignalHandler()
#2 0x7f49814a9cb0 <unknown>
#3 0x7f4984b74659 pthread_join
#4 0x0000023ea6a5 base::PlatformThread::Join()
#5 0x0000023f0371 base::Thread::Stop()
#6 0x000001968c13 content::BrowserProcessSubThread::~BrowserProcessSubThread()
#7 0x0000019606b1 content::(anonymous namespace)::ResetThread_IO()
#8 0x00000195f6aa content::BrowserMainLoop::ShutdownThreadsAndCleanUp()
#9 0x000001961a01 content::BrowserMainRunnerImpl::Shutdown()
#10 0x000001f64aed ShellBrowserMain()
#11 0x000001f5b8d2 content::ShellMainDelegate::RunProcess()
#12 0x00000189387a content::RunNamedProcessTypeMain()
#13 0x00000189444c content::ContentMainRunnerImpl::Run()
#14 0x00000347683f service_manager::Main()
#15 0x000000e3c262 content::ContentMain()
#16 0x000001f1ae97 content::BrowserTestBase::SetUp()
#17 0x000001f129ae content::ContentBrowserTest::SetUp()
#18 0x00000213315e testing::Test::Run()
#19 0x000002133ca0 testing::TestInfo::Run()
#20 0x0000021341c7 testing::TestCase::Run()
#21 0x00000213b207 testing::internal::UnitTestImpl::RunAllTests()
#22 0x00000213ae87 testing::UnitTest::Run()
#23 0x000001f3d691 base::TestSuite::Run()
#24 0x000001f161f4 content::ContentTestLauncherDelegate::RunTestSuite()
#25 0x000001f30039 content::LaunchTests()
#26 0x000001f161b3 main
#27 0x7f4981494f45 __libc_start_main
#28 0x0000004a59c2 <unknown>

Sadrul, any idea who would be a good person to look at this?