For example:
https://ci.chromium.org/buildbot/chromium.clang/ToTLinux/2120
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/win%20trunk/builds/82555

From the latter:

failures:
SafeBrowsingBlockingPageTest.MalwarePageProceed
DownloadProtectionServiceFlagTest.CheckClientDownloadOverridenByFlag
NotificationImageReporterTest.NoReportWithoutScout
DownloadProtectionServiceTest.CheckClientDownloadBlob
DownloadProtectionServiceTest.CheckClientDownloadValidateRequestTabHistory
SafeBrowsingBlockingPageTest.ExtendedReportingNotShownInIncognito
NotificationImageReporterTest.ImageDownscaling
DownloadProtectionServiceFlagTest.CheckClientDownloadZipOverridenByFlag
SafeBrowsingUIManagerTest.IOCallbackProceed
NotificationImageReporterTest.NoReportOnWhitelistedUrl
SafeBrowsingUIManagerTest.VisibleSecurityStateChangedForUnsafeSubresource
NotificationImageReporterTest.NoReportWithoutSBER
SafeBrowsingBlockingPageTest.NavigatingBackAndForth
SafeBrowsingUIManagerTest.UICallbackProceed
SafeBrowsingBlockingPageTest.PageWithMalwareResourceProceed
DownloadProtectionServiceTest.CheckClientDownloadWhitelistedUrlWithoutSampling
SafeBrowsingBlockingPageTest.MalwareReportsDisabled
DownloadProtectionServiceTest.TestDownloadRequestTimeout
SafeBrowsingBlockingPageTest.PageWithMultipleMalwareResourceProceedThenDontProceed
DownloadProtectionServiceTest.PPAPIDownloadRequest_WhitelistedURL
SafeBrowsingBlockingPageTest.PageWithMultipleMalwareResourceDontProceed
DownloadProtectionServiceTest.PPAPIDownloadRequest_SupportedAlternate
SafeBrowsingBlockingPageTest.MalwarePageDontProceed
DownloadProtectionServiceTest.PPAPIDownloadRequest_Payload
DownloadProtectionServiceTest.PPAPIDownloadRequest_FetchFailed
DownloadProtectionServiceTest.CheckClientDownloadNotABinary
DownloadProtectionServiceTest.CheckClientDownloadSampledFile
NotificationImageReporterTest.NoReportWithoutReportingEnabled
DownloadProtectionServiceTest.CheckClientDownloadWhitelistedUrlWithSampling
NotificationImageReporterTest.MaxReportsPerDay
SafeBrowsingBlockingPageTest.PageWithMalwareResourceDontProceed
SafeBrowsingBlockingPageTest.ProceedThenDontProceed
DownloadProtectionServiceTest.CheckClientDownloadReportCorruptZip
DownloadProtectionServiceTest.PPAPIDownloadRequest_SupportedDefault
DownloadProtectionServiceTest.CheckClientDownloadZip
SafeBrowsingBlockingPageTest.MalwareReportsToggling
DownloadProtectionServiceTest.CheckClientDownloadFetchFailed
DownloadProtectionServiceTest.CheckClientDownloadValidateRequest
DownloadProtectionServiceTest.PPAPIDownloadRequest_InvalidResponse
DownloadProtectionServiceTest.CheckClientDownloadSuccess
SafeBrowsingUIManagerTest.UICallbackDontProceed
SafeBrowsingBlockingPageTest.PageWithMultipleMalwareResourceProceed
DownloadProtectionServiceTest.CheckClientDownloadData
DownloadProtectionServiceTest.CheckClientDownloadValidateRequestNoSignature
DownloadProtectionServiceTest.CheckClientDownloadHTTPS
SafeBrowsingUIManagerTest.IOCallbackDontProceed
SafeBrowsingBlockingPageTest.ExtendedReportingNotShownNotAllowExtendedReporting
DownloadProtectionServiceTest.TestCheckDownloadUrl
NotificationImageReporterTest.ReportSuccess
DownloadProtectionServiceTest.CheckClientDownloadInvalidUrl


Looking at one of those:

DownloadProtectionServiceFlagTest.CheckClientDownloadOverridenByFlag (run #1):
[ RUN      ] DownloadProtectionServiceFlagTest.CheckClientDownloadOverridenByFlag
Received fatal exception EXCEPTION_ACCESS_VIOLATION
Backtrace:
	network::SocketFactory::SocketFactory [0x0000000142C195CE+30] (C:\b\c\b\win_trunk\src\services\network\socket_factory.cc:25)
	network::NetworkContext::NetworkContext [0x0000000142C0C47B+251] (C:\b\c\b\win_trunk\src\services\network\network_context.cc:153)
	safe_browsing::SafeBrowsingNetworkContext::SharedURLLoaderFactory::InternalState::InitOnIO [0x0000000140F400FF+111] (C:\b\c\b\win_trunk\src\components\safe_browsing\browser\safe_browsing_network_context.cc:101)
	base::internal::Invoker<base::internal::BindState<void (safe_browsing::SafeBrowsingNetworkContext::SharedURLLoaderFactory::InternalState::*)(scoped_refptr<net::URLRequestContextGetter>, mojo::InterfaceRequest<network::mojom::NetworkContext>),scoped_refptr [0x0000000140F401BE+94] (C:\b\c\b\win_trunk\src\base\bind_internal.h:572)
	base::debug::TaskAnnotator::RunTask [0x0000000141FE76E5+309] (C:\b\c\b\win_trunk\src\base\debug\task_annotator.cc:101)
	base::MessageLoop::RunTask [0x0000000141F83DFC+572] (C:\b\c\b\win_trunk\src\base\message_loop\message_loop.cc:355)
	base::MessageLoop::DoWork [0x0000000141F84348+408] (C:\b\c\b\win_trunk\src\base\message_loop\message_loop.cc:408)
	base::MessagePumpForIO::DoRunLoop [0x0000000141FD05CA+330] (C:\b\c\b\win_trunk\src\base\message_loop\message_pump_win.cc:481)
	base::MessagePumpWin::Run [0x0000000141FCF8C8+104] (C:\b\c\b\win_trunk\src\base\message_loop\message_pump_win.cc:59)
	base::RunLoop::Run [0x0000000141F68BC1+49] (C:\b\c\b\win_trunk\src\base\run_loop.cc:136)
	safe_browsing::DownloadProtectionServiceFlagTest_CheckClientDownloadOverridenByFlag_Test::TestBody [0x000000013FE70B50+1376] (C:\b\c\b\win_trunk\src\chrome\browser\safe_browsing\download_protection\download_protection_service_unittest.cc:2487)
	testing::Test::Run [0x0000000140150EF7+183] (C:\b\c\b\win_trunk\src\third_party\googletest\src\googletest\src\gtest.cc:2498)
	testing::TestInfo::Run [0x0000000140151806+214] (C:\b\c\b\win_trunk\src\third_party\googletest\src\googletest\src\gtest.cc:2671)
	testing::TestCase::Run [0x0000000140151C9A+250] (C:\b\c\b\win_trunk\src\third_party\googletest\src\googletest\src\gtest.cc:2784)
	testing::internal::UnitTestImpl::RunAllTests [0x0000000140158E1E+638] (C:\b\c\b\win_trunk\src\third_party\googletest\src\googletest\src\gtest.cc:5046)
	testing::UnitTest::Run [0x0000000140158A95+165] (C:\b\c\b\win_trunk\src\third_party\googletest\src\googletest\src\gtest.cc:4663)
	base::TestSuite::Run [0x0000000141950E96+118] (C:\b\c\b\win_trunk\src\base\test\test_suite.cc:275)
	base::`anonymous namespace'::LaunchUnitTestsInternal [0x0000000141951E0A+330] (C:\b\c\b\win_trunk\src\base\test\launcher\unit_test_launcher.cc:225)
	base::LaunchUnitTests [0x0000000141951C88+168] (C:\b\c\b\win_trunk\src\base\test\launcher\unit_test_launcher.cc:576)
	main [0x0000000144B02BB1+269] (C:\b\c\b\win_trunk\src\chrome\test\base\run_all_unittests.cc:30)
	__scrt_common_main_seh [0x00000001455A8649+285] (f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:283)
	BaseThreadInitThunk [0x00000000772259CD+13]
	RtlUserThreadStart [0x000000007735B981+33]


(Not really blocking the Clang roll, but it breaks our buildbots so tracking it as a blocker.)