Failed here:

https://ci.chromium.org/p/chromium/builders/luci.chromium.try/linux-chromeos-dbg/235

https://logs.chromium.org/v/?s=chromium%2Fbuildbucket%2Fcr-buildbucket.appspot.com%2F8941567759227913376%2F%2B%2Fsteps%2Fmash_browser_tests__with_patch_%2F0%2Flogs%2FWebUIWebViewBrowserTest.ExecuteScriptCode%2F0

[27837:27864:0708/071951.187693:FATAL:window_manager_state.cc(515)] Check failed: tree.
#0 0x7fad50cbfc4d base::debug::StackTrace::StackTrace()
#1 0x7fad509d8a7c base::debug::StackTrace::StackTrace()
#2 0x7fad50a4247d logging::LogMessage::~LogMessage()
#3 0x7fad3d18391f ui::ws::WindowManagerState::GetEventTargetClientId()
#4 0x7fad3d133653 ui::ws::EventProcessor::GetWindowForMouseCursor()
#5 0x7fad3d133591 ui::ws::EventProcessor::GetCurrentMouseCursor()
#6 0x7fad3d18364c ui::ws::WindowManagerState::UpdateNativeCursorFromEventProcessor()
#7 0x7fad3d13a195 ui::ws::EventProcessor::UpdateCursorProvider()
#8 0x7fad3d1351ec ui::ws::EventProcessor::UpdateCursorProviderByLastKnownLocationOnFoundWindow()
#9 0x7fad3b723bfd _ZN4base8internal13FunctorTraitsIMN3ash21HighlighterResultViewEFvRKNS_9TimeDeltaERKNS_17RepeatingCallbackIFvvEEEEvE6InvokeISD_PS3_JS6_SB_EEEvT_OT0_DpOT1_
#10 0x7fad3b723b2a _ZN4base8internal12InvokeHelperILb0EvE8MakeItSoIRKMN3ash21HighlighterResultViewEFvRKNS_9TimeDeltaERKNS_17RepeatingCallbackIFvvEEEEJPS5_S8_SD_EEEvOT_DpOT0_
#11 0x7fad3d13b705 _ZN4base8internal7InvokerINS0_9BindStateIMN2ui2ws14EventProcessorEFvRKNS4_13EventLocationERKNS4_13DeepestWindowEEJNS0_17UnretainedWrapperIS5_EEEEEFvS8_SB_EE7RunImplISD_NSt3__15tupleIJSF_EEEJLm0EEEEvOT_OT0_NSK_16integer_sequenceImJXspT1_EEEES8_SB_
#12 0x7fad3d13b639 _ZN4base8internal7InvokerINS0_9BindStateIMN2ui2ws14EventProcessorEFvRKNS4_13EventLocationERKNS4_13DeepestWindowEEJNS0_17UnretainedWrapperIS5_EEEEEFvS8_SB_EE7RunOnceEPNS0_13BindStateBaseES8_SB_
#13 0x7fad3c1d228e _ZNO4base12OnceCallbackIFvRKNSt3__112basic_stringItNS_18string16_internals20string16_char_traitsENS1_9allocatorItEEEERKNS2_IcNS1_11char_traitsIcEENS5_IcEEEEEE3RunES9_SF_
#14 0x7fad3d14020a ui::ws::EventTargeter::FindTargetForLocationNow()
#15 0x7fad3d140145 ui::ws::EventTargeter::FindTargetForLocation()
#16 0x7fad3d1348b5 ui::ws::EventProcessor::UpdateCursorProviderByLastKnownLocation()
#17 0x7fad3d193f5e ui::ws::WindowServer::UpdateNativeCursorFromMouseLocation()
#18 0x7fad3d194c4d ui::ws::WindowServer::OnWindowHierarchyChanged()
#19 0x7fad3d156c75 ui::ws::ServerWindow::Remove()
#20 0x7fad3d155b8c ui::ws::ServerWindow::~ServerWindow()
#21 0x7fad3d156cb9 ui::ws::ServerWindow::~ServerWindow()
#22 0x7fad3d19e645 ui::ws::WindowTree::DestroyWindows()
#23 0x7fad3d19d7f9 ui::ws::WindowTree::~WindowTree()
#24 0x7fad3d19e819 ui::ws::WindowTree::~WindowTree()
#25 0x7fad3d18a99d ui::ws::WindowServer::DestroyTree()
#26 0x7fad3b8baf20 _ZN4base8internal13FunctorTraitsIMN3ash9ShelfViewEFvPN5views4ViewEEvE6InvokeIS8_PS3_JS6_EEEvT_OT0_DpOT1_
#27 0x7fad3b8bae4f _ZN4base8internal12InvokeHelperILb0EvE8MakeItSoIMN3ash9ShelfViewEFvPN5views4ViewEEJPS5_S8_EEEvOT_DpOT0_
#28 0x7fad3d1d2cc2 _ZN4base8internal7InvokerINS0_9BindStateIMN2ui2ws12WindowServerEFvPNS4_10WindowTreeEEJNS0_17UnretainedWrapperIS5_EENSA_IS6_EEEEEFvvEE7RunImplIRKS9_RKNSt3__15tupleIJSB_SC_EEEJLm0ELm1EEEEvOT_OT0_NSJ_16integer_sequenceImJXspT1_EEEE
#29 0x7fad3d1d2bcc _ZN4base8internal7InvokerINS0_9BindStateIMN2ui2ws12WindowServerEFvPNS4_10WindowTreeEEJNS0_17UnretainedWrapperIS5_EENSA_IS6_EEEEEFvvEE3RunEPNS0_13BindStateBaseE
#30 0x7fad4b8eedce _ZNO4base12OnceCallbackIFvvEE3RunEv
#31 0x7fad4b8ffa99 mojo::InterfaceEndpointClient::NotifyError()
#32 0x7fad4b90c2cd mojo::internal::MultiplexRouter::ProcessNotifyErrorTask()
#33 0x7fad4b909a90 mojo::internal::MultiplexRouter::ProcessTasks()
#34 0x7fad4b9082ef mojo::internal::MultiplexRouter::OnPipeConnectionError()
#35 0x7fad4b8f933d _ZN4base8internal13FunctorTraitsIMN4mojo8internal19ControlMessageProxyEFvvEvE6InvokeIS6_PS4_JEEEvT_OT0_DpOT1_
#36 0x7fad4b8f9284 _ZN4base8internal12InvokeHelperILb0EvE8MakeItSoIRKMN4mojo8internal19ControlMessageProxyEFvvEJPS6_EEEvOT_DpOT0_
#37 0x7fad4b9110b5 _ZN4base8internal7InvokerINS0_9BindStateIMN4mojo8internal15MultiplexRouterEFvvEJNS0_17UnretainedWrapperIS5_EEEEEFvvEE7RunImplIRKS7_RKNSt3__15tupleIJS9_EEEJLm0EEEEvOT_OT0_NSG_16integer_sequenceImJXspT1_EEEE
#38 0x7fad4b910ffc _ZN4base8internal7InvokerINS0_9BindStateIMN4mojo8internal15MultiplexRouterEFvvEJNS0_17UnretainedWrapperIS5_EEEEEFvvEE3RunEPNS0_13BindStateBaseE
#39 0x7fad4b8eedce _ZNO4base12OnceCallbackIFvvEE3RunEv
#40 0x7fad4b8ec358 mojo::Connector::HandleError()
#41 0x7fad4b8ed877 mojo::Connector::OnHandleReadyInternal()
#42 0x7fad4b8ed78b mojo::Connector::OnWatcherHandleReady()
#43 0x7fad4b8f0fbf _ZN4base8internal13FunctorTraitsIMN4mojo9ConnectorEFvjEvE6InvokeIS5_PS3_JjEEEvT_OT0_DpOT1_
#44 0x7fad4b8f0eef _ZN4base8internal12InvokeHelperILb0EvE8MakeItSoIRKMN4mojo9ConnectorEFvjEJPS5_jEEEvOT_DpOT0_
#45 0x7fad4b8f0e85 _ZN4base8internal7InvokerINS0_9BindStateIMN4mojo9ConnectorEFvjEJNS0_17UnretainedWrapperIS4_EEEEEFvjEE7RunImplIRKS6_RKNSt3__15tupleIJS8_EEEJLm0EEEEvOT_OT0_NSF_16integer_sequenceImJXspT1_EEEEOj
#46 0x7fad4b8f0dbb _ZN4base8internal7InvokerINS0_9BindStateIMN4mojo9ConnectorEFvjEJNS0_17UnretainedWrapperIS4_EEEEEFvjEE3RunEPNS0_13BindStateBaseEj
#47 0x7fad4b8e83ae _ZNKR4base17RepeatingCallbackIFvjEE3RunEj
#48 0x7fad4b8f013f mojo::SimpleWatcher::DiscardReadyState()
#49 0x7fad4b8f03bf _ZN4base8internal13FunctorTraitsIPFvRKNS_17RepeatingCallbackIFvjEEEjRKN4mojo18HandleSignalsStateEEvE6InvokeIRKSC_JS6_jSA_EEEvOT_DpOT0_
#50 0x7fad4b8f035d _ZN4base8internal12InvokeHelperILb0EvE8MakeItSoIRKPFvRKNS_17RepeatingCallbackIFvjEEEjRKN4mojo18HandleSignalsStateEEJS8_jSC_EEEvOT_DpOT0_
#51 0x7fad4b8f0300 _ZN4base8internal7InvokerINS0_9BindStateIPFvRKNS_17RepeatingCallbackIFvjEEEjRKN4mojo18HandleSignalsStateEEJS5_EEEFvjSB_EE7RunImplIRKSD_RKNSt3__15tupleIJS5_EEEJLm0EEEEvOT_OT0_NSK_16integer_sequenceImJXspT1_EEEEOjSB_
#52 0x7fad4b8f0236 _ZN4base8internal7InvokerINS0_9BindStateIPFvRKNS_17RepeatingCallbackIFvjEEEjRKN4mojo18HandleSignalsStateEEJS5_EEEFvjSB_EE3RunEPNS0_13BindStateBaseEjSB_
#53 0x7fad50fad80e _ZNKR4base17RepeatingCallbackIFvjRKN4mojo18HandleSignalsStateEEE3RunEjS4_
#54 0x7fad50fad17b mojo::SimpleWatcher::OnHandleReady()
#55 0x7fad50fadfc3 _ZN4base8internal13FunctorTraitsIMN4mojo13SimpleWatcherEFvijRKNS2_18HandleSignalsStateEEvE6InvokeIS8_RKNS_7WeakPtrIS3_EEJRKiRKjS6_EEEvT_OT0_DpOT1_
#56 0x7fad50fadf05 _ZN4base8internal12InvokeHelperILb1EvE8MakeItSoIRKMN4mojo13SimpleWatcherEFvijRKNS4_18HandleSignalsStateEERKNS_7WeakPtrIS5_EEJRKiRKjS8_EEEvOT_OT0_DpOT1_
#57 0x7fad50fade62 _ZN4base8internal7InvokerINS0_9BindStateIMN4mojo13SimpleWatcherEFvijRKNS3_18HandleSignalsStateEEJNS_7WeakPtrIS4_EEijS5_EEEFvvEE7RunImplIRKS9_RKNSt3__15tupleIJSB_ijS5_EEEJLm0ELm1ELm2ELm3EEEEvOT_OT0_NSI_16integer_sequenceImJXspT1_EEEE
#58 0x7fad50fadcdc _ZN4base8internal7InvokerINS0_9BindStateIMN4mojo13SimpleWatcherEFvijRKNS3_18HandleSignalsStateEEJNS_7WeakPtrIS4_EEijS5_EEEFvvEE3RunEPNS0_13BindStateBaseE
#59 0x7fad5098a1ce _ZNO4base12OnceCallbackIFvvEE3RunEv
#60 0x7fad509d9e6a base::debug::TaskAnnotator::RunTask()
#61 0x7fad50a6390a base::internal::IncomingTaskQueue::RunTask()



Other tests in that file are disabled for cros too, but my guess is that this is one of the few bots running tests in debug and the test is flaky in debug because the timing is different there (i.e. the bug is racy everywhere and it just manifests only on that bot).


If it takes a while to investigate, please disable the test in the meantime.