Running a Debug build of unit_tests with --gtest_filter=SyncInternal* the run reliably fails with:

[ RUN      ] SyncInternalsMessageHandlerTest.AddRemoveObserversDisallowJavascript
[243308:243308:0504/045118.130708:3681726076554:FATAL:sequenced_task_runner_handle.cc(33)] Check failed: ThreadTaskRunnerHandle::IsSet(). Error: This caller requires a sequenced context (i.e. the current task needs to run from a SequencedTaskRunner).
#0 0x7f532701789d base::debug::StackTrace::StackTrace()
#1 0x7f5326d4254c base::debug::StackTrace::StackTrace()
#2 0x7f5326db3e5a logging::LogMessage::~LogMessage()
#3 0x7f5326f31cd9 base::SequencedTaskRunnerHandle::Get()
#4 0x7f532b766305 mojo::internal::GetTaskRunnerToUseFromUserProvidedTaskRunner()
#5 0x7f532b73c88e mojo::internal::InterfacePtrStateBase::Bind()
#6 0x000002178e78 mojo::internal::InterfacePtrState<>::Bind()
#7 0x000002178962 mojo::InterfacePtr<>::Bind()
#8 0x00000217777c mojo::MakeRequest<>()
#9 0x0000076f79f7 resource_coordinator::PageSignalReceiver::AddObserver()
#10 0x000007961ba5 resource_coordinator::TabManager::ResourceCoordinatorSignalObserver::ResourceCoordinatorSignalObserver()
#11 0x00000794dd46 resource_coordinator::TabManager::TabManager()
#12 0x00000681a9a8 TestingBrowserProcess::GetTabManager()
#13 0x000006814a23 (anonymous namespace)::ChromeUnitTestSuiteInitializer::OnTestStart()
#14 0x000004b4a715 testing::internal::TestEventRepeater::OnTestStart()
#15 0x000004b463b1 testing::TestInfo::Run()
#16 0x000004b46ecf testing::TestCase::Run()
#17 0x000004b59288 testing::internal::UnitTestImpl::RunAllTests()
#18 0x000004b6b58e testing::internal::HandleSehExceptionsInMethodIfSupported<>()
#19 0x000004b63612 testing::internal::HandleExceptionsInMethodIfSupported<>()
#20 0x000004b58ee7 testing::UnitTest::Run()
#21 0x00000684c071 RUN_ALL_TESTS()
#22 0x000006848a3b base::TestSuite::Run()
#23 0x0000069a4f80 content::UnitTestTestSuite::Run()
#24 0x000001c96b6d _ZN4base8internal13FunctorTraitsIMNS_7RunLoopEFvvEvE6InvokeIS4_PS2_JEEEvT_OT0_DpOT1_
#25 0x000001c96ae4 _ZN4base8internal12InvokeHelperILb0EvE8MakeItSoIMNS_7RunLoopEFvvEJPS4_EEEvOT_DpOT0_
#26 0x000001c96a95 _ZN4base8internal7InvokerINS0_9BindStateIMNS_7RunLoopEFvvEJNS0_17UnretainedWrapperIS3_EEEEEFvvEE7RunImplIS5_NSt3__15tupleIJS7_EEEJLm0EEEEvOT_OT0_NSC_16integer_sequenceImJXspT1_EEEE
#27 0x000002285adc _ZN4base8internal7InvokerINS0_9BindStateIM13ThreadWatcherFvvEJNS0_17UnretainedWrapperI19CustomThreadWatcherEEEEEFvvEE3RunEPNS0_13BindStateBaseE
#28 0x0000052f88fe _ZNO4base12OnceCallbackIFivEE3RunEv
#29 0x0000068519d5 base::(anonymous namespace)::LaunchUnitTestsInternal()
#30 0x000006851825 base::LaunchUnitTests()
#31 0x000006832a31 main
#32 0x7f530abbe2b1 __libc_start_main
#33 0x000001c7c02a _start

This crash causes the remaining tests in the same batch to be treated as UNKNOWN / failed.