DesktopWindowTreeHostMusTest.StackAbove fails in views_mus_unittests with WS2

See work to use test_ws / ws2 in views_mus_unittests here:
  https://chromium-review.googlesource.com/c/chromium/src/+/1138749

[ RUN      ] DesktopWindowTreeHostMusTest.StackAbove
[176719:181220:0717/095621.900302:3968880961957:INFO:service_process_launcher.cc(200)] Launched child process pid=181255, instance=, name=test_ws, user_id=505C0EE9-3013-43C0-82B0-A84F50CF8D84
[181255:181255:0717/095622.143156:3968881204870:ERROR:window_service.cc(30)] Not implemented reached in void ui::ws2::(anonymous namespace)::BindEventInjectorRequest(ui::mojom::EventInjectorRequest)
[181255:181255:0717/095622.143290:3968881204939:ERROR:window_service.cc(34)] Not implemented reached in void ui::ws2::(anonymous namespace)::BindGpuRequest(ui::mojom::GpuRequest)
[181255:181255:0717/095622.143348:3968881204996:ERROR:window_service.cc(34)] Not implemented reached in void ui::ws2::(anonymous namespace)::BindGpuRequest(ui::mojom::GpuRequest)
[181255:181255:0717/095622.143390:3968881205037:ERROR:window_service.cc(39)] Not implemented reached in void ui::ws2::(anonymous namespace)::BindDiscardableSharedMemoryManagerRequest(discardable_memory::mojom::DiscardableSharedMemoryManagerRequest)
[181255:181255:0717/095622.151835:3968881213486:ERROR:window_tree.cc(1316)] Not implemented reached in virtual void ui::ws2::WindowTree::SetHitTestMask(ui::Id, const base::Optional<gfx::Rect> &)
../../ui/aura/test/mus/change_completion_waiter.cc:106: Failure
Expected equality of these values:
  success_
    Which is: true
  success
    Which is: false
Stack trace:
#0 0x0000006e147c testing::internal::UnitTestImpl::CurrentOsStackTraceExceptTop()
#1 0x0000006e0e59 testing::internal::AssertHelper::operator=()
#2 0x00000072dee2 aura::test::ChangeCompletionWaiter::OnChangeCompleted()
#3 0x7f095542bae7 aura::WindowTreeClient::OnChangeCompleted()
#4 0x7f0955465d95 ui::mojom::WindowTreeClientStubDispatch::Accept()
#5 0x7f0954c3f216 mojo::InterfaceEndpointClient::HandleValidatedMessage()
#6 0x7f0954c3eb46 mojo::FilterChain::Accept()
#7 0x7f0954c405a5 mojo::InterfaceEndpointClient::HandleIncomingMessage()
#8 0x7f0954c46bfc mojo::internal::MultiplexRouter::ProcessIncomingMessage()
#9 0x7f0954c46000 mojo::internal::MultiplexRouter::Accept()
#10 0x7f0954c3eb46 mojo::FilterChain::Accept()
#11 0x7f0954c39e23 mojo::Connector::ReadSingleMessage()
#12 0x7f0954c3a871 mojo::Connector::ReadAllAvailableMessages()
#13 0x7f0954c3a719 mojo::Connector::OnHandleReadyInternal()
#14 0x7f0954c3af67 mojo::SimpleWatcher::DiscardReadyState()
#15 0x7f0954ec7704 mojo::SimpleWatcher::OnHandleReady()
#16 0x7f0954ec7c11 _ZN4base8internal7InvokerINS0_9BindStateIMN4mojo13SimpleWatcherEFvijRKNS3_18HandleSignalsStateEEJNS_7WeakPtrIS4_EEijS5_EEEFvvEE7RunImplIRKS9_RKNSt3__15tupleIJSB_ijS5_EEEJLm0ELm1ELm2ELm3EEEEvOT_OT0_NSI_16integer_sequenceImJXspT1_EEEE
#17 0x7f0955f5ba15 base::debug::TaskAnnotator::RunTask()
#18 0x7f0955f8894a base::MessageLoop::RunTask()
#19 0x7f0955f88cda base::MessageLoop::DeferOrRunPendingTask()
#20 0x7f0955f88fd7 base::MessageLoop::DoWork()
#21 0x7f09560654e9 base::MessagePumpLibevent::Run()
#22 0x7f0955f88374 base::MessageLoop::Run()
#23 0x7f0955fba319 base::RunLoop::Run()
#24 0x00000072dd82 aura::test::ChangeCompletionWaiter::Wait()
#25 0x0000004a8766 views::DesktopWindowTreeHostMusTest_StackAbove_Test::TestBody()

[176719:176719:0717/095622.159601:3968881221251:ERROR:in_flight_change.cc(103)] change failed, type=16
[176719:176719:0717/095622.159626:3968881221273:FATAL:in_flight_change.cc(104)] Check failed: false. 
#0 0x7f095604548c base::debug::StackTrace::StackTrace()
#1 0x7f0955f787bb logging::LogMessage::~LogMessage()
#2 0x7f09554111e4 aura::CrashInFlightChange::ChangeFailed()
#3 0x7f095542bb46 aura::WindowTreeClient::OnChangeCompleted()
#4 0x7f0955465d95 ui::mojom::WindowTreeClientStubDispatch::Accept()
#5 0x7f0954c3f216 mojo::InterfaceEndpointClient::HandleValidatedMessage()
#6 0x7f0954c3eb46 mojo::FilterChain::Accept()
#7 0x7f0954c405a5 mojo::InterfaceEndpointClient::HandleIncomingMessage()
#8 0x7f0954c46bfc mojo::internal::MultiplexRouter::ProcessIncomingMessage()
#9 0x7f0954c46000 mojo::internal::MultiplexRouter::Accept()
#10 0x7f0954c3eb46 mojo::FilterChain::Accept()
#11 0x7f0954c39e23 mojo::Connector::ReadSingleMessage()
#12 0x7f0954c3a871 mojo::Connector::ReadAllAvailableMessages()
#13 0x7f0954c3a719 mojo::Connector::OnHandleReadyInternal()
#14 0x7f0954c3af67 mojo::SimpleWatcher::DiscardReadyState()
#15 0x7f0954ec7704 mojo::SimpleWatcher::OnHandleReady()
#16 0x7f0954ec7c11 _ZN4base8internal7InvokerINS0_9BindStateIMN4mojo13SimpleWatcherEFvijRKNS3_18HandleSignalsStateEEJNS_7WeakPtrIS4_EEijS5_EEEFvvEE7RunImplIRKS9_RKNSt3__15tupleIJSB_ijS5_EEEJLm0ELm1ELm2ELm3EEEEvOT_OT0_NSI_16integer_sequenceImJXspT1_EEEE
#17 0x7f0955f5ba15 base::debug::TaskAnnotator::RunTask()
#18 0x7f0955f8894a base::MessageLoop::RunTask()
#19 0x7f0955f88cda base::MessageLoop::DeferOrRunPendingTask()
#20 0x7f0955f88fd7 base::MessageLoop::DoWork()
#21 0x7f09560654e9 base::MessagePumpLibevent::Run()
#22 0x7f0955f88374 base::MessageLoop::Run()
#23 0x7f0955fba319 base::RunLoop::Run()
#24 0x00000072dd82 aura::test::ChangeCompletionWaiter::Wait()
#25 0x0000004a8766 views::DesktopWindowTreeHostMusTest_StackAbove_Test::TestBody()
#26 0x0000006e6362 testing::Test::Run()
#27 0x0000006e6e00 testing::TestInfo::Run()
#28 0x0000006e7317 testing::TestCase::Run()
#29 0x0000006f2937 testing::internal::UnitTestImpl::RunAllTests()
#30 0x0000006f24ad testing::UnitTest::Run()
#31 0x0000007183c1 base::TestSuite::Run()
#32 0x000000719ded base::(anonymous namespace)::LaunchUnitTestsInternal()
#33 0x000000719c51 base::LaunchUnitTests()
#34 0x0000004be90a views::ViewsTestSuite::RunTests()
#35 0x0000004afc2f main
#36 0x7f095312a2b1 __libc_start_main
#37 0x00000049feea _start

[145/905] DesktopWindowTreeHostMusTest.StackAbove (CRASHED)