nick@ is on leave and I don't have cycles for this at the moment. creis@ Do you know if anyone can take a look at this?

Yes.  Looks like a hit testing crash in the log (below).  I suspect it's related to the recent Viz hit testing work in support of Site Isolation.

Navid and Sadrul, can you see if it's similar to the other flaky test failures we've been seeing?

[1:1:0111/040146.014236:FATAL:PaintLayer.cpp(1885)] Check failed: GetLayoutObject().GetDocument().Lifecycle().GetState() >= DocumentLifecycle::kCompositingClean.
#0 0x0000f723e017 base::debug::StackTrace::StackTrace()
#1 0x0000f723c02c base::debug::StackTrace::StackTrace()
#2 0x0000f72d960e logging::LogMessage::~LogMessage()
#3 0x0000e289081e blink::PaintLayer::HitTestLayer()
#4 0x0000e2890314 blink::PaintLayer::HitTest()
#5 0x0000e245897c blink::LayoutView::HitTestNoLifecycleUpdate()
#6 0x0000e2458509 blink::LayoutView::HitTest()
#7 0x0000e1f92e47 blink::EventHandler::HitTestResultAtPoint()
#8 0x0000e1c0c5d9 blink::WebFrameWidgetImpl::HitTestResultForRootFramePos()
#9 0x0000e1c08094 blink::WebFrameWidgetImpl::CoreHitTestResultAt()
#10 0x0000e1c07f00 blink::WebFrameWidgetImpl::HitTestResultAt()
#11 0x0000ef77b3eb content::RenderWidgetInputHandler::GetFrameSinkIdAtPoint()
#12 0x0000ef9b51c7 content::RenderWidget::GetFrameSinkIdAtPoint()
#13 0x0000ef771213 content::InputTargetClientImpl::FrameSinkIdAt()
#14 0x0000ed03f668 viz::mojom::InputTargetClientStubDispatch::AcceptWithResponder()
#15 0x0000ef771683 viz::mojom::InputTargetClientStub<>::AcceptWithResponder()
#16 0x0000f252053e mojo::InterfaceEndpointClient::HandleValidatedMessage()
#17 0x0000f251f99d mojo::InterfaceEndpointClient::HandleIncomingMessageThunk::Accept()
#18 0x0000f251dfeb mojo::FilterChain::Accept()
#19 0x0000f2524239 mojo::InterfaceEndpointClient::HandleIncomingMessage()
#20 0x0000f253df3d mojo::internal::MultiplexRouter::ProcessIncomingMessage()
#21 0x0000f253d1e4 mojo::internal::MultiplexRouter::Accept()
#22 0x0000f251dfeb mojo::FilterChain::Accept()
#23 0x0000f250db1b mojo::Connector::ReadSingleMessage()
#24 0x0000f250ed64 mojo::Connector::ReadAllAvailableMessages()
#25 0x0000f250eb15 mojo::Connector::OnHandleReadyInternal()
#26 0x0000f250e9ba mojo::Connector::OnWatcherHandleReady()
#27 0x0000f25133c2 _ZN4base8internal13FunctorTraitsIMN4mojo9ConnectorEFvjEvE6InvokeIPS3_JjEEEvS5_OT_DpOT0_
#28 0x0000f25132d0 _ZN4base8internal12InvokeHelperILb0EvE8MakeItSoIRKMN4mojo9ConnectorEFvjEJPS5_jEEEvOT_DpOT0_
#29 0x0000f2513230 _ZN4base8internal7InvokerINS0_9BindStateIMN4mojo9ConnectorEFvjEJNS0_17UnretainedWrapperIS4_EEEEEFvjEE7RunImplIRKS6_RKNSt3__15tupleIJS8_EEEJLj0EEEEvOT_OT0_NSF_16integer_sequenceIjJXspT1_EEEEOj
#30 0x0000f2513108 _ZN4base8internal7InvokerINS0_9BindStateIMN4mojo9ConnectorEFvjEJNS0_17UnretainedWrapperIS4_EEEEEFvjEE3RunEPNS0_13BindStateBaseEj
#31 0x0000f2507357 _ZNKR4base17RepeatingCallbackIFvjEE3RunEj
#32 0x0000f2511f21 mojo::SimpleWatcher::DiscardReadyState()
#33 0x0000f25122f1 _ZN4base8internal13FunctorTraitsIPFvRKNS_17RepeatingCallbackIFvjEEEjRKN4mojo18HandleSignalsStateEEvE6InvokeIJS6_jSA_EEEvSC_DpOT_
#34 0x0000f251224e _ZN4base8internal12InvokeHelperILb0EvE8MakeItSoIRKPFvRKNS_17RepeatingCallbackIFvjEEEjRKN4mojo18HandleSignalsStateEEJS8_jSC_EEEvOT_DpOT0_
#35 0x0000f25121b2 _ZN4base8internal7InvokerINS0_9BindStateIPFvRKNS_17RepeatingCallbackIFvjEEEjRKN4mojo18HandleSignalsStateEEJS5_EEEFvjSB_EE7RunImplIRKSD_RKNSt3__15tupleIJS5_EEEJLj0EEEEvOT_OT0_NSK_16integer_sequenceIjJXspT1_EEEEOjSB_
#36 0x0000f251206c _ZN4base8internal7InvokerINS0_9BindStateIPFvRKNS_17RepeatingCallbackIFvjEEEjRKN4mojo18HandleSignalsStateEEJS5_EEEFvjSB_EE3RunEPNS0_13BindStateBaseEjSB_
#37 0x0000f24a3e1d _ZNKR4base17RepeatingCallbackIFvjRKN4mojo18HandleSignalsStateEEE3RunEjS4_
#38 0x0000f24a349d mojo::SimpleWatcher::OnHandleReady()
#39 0x0000f24a491b _ZN4base8internal13FunctorTraitsIMN4mojo13SimpleWatcherEFvijRKNS2_18HandleSignalsStateEEvE6InvokeIRKNS_7WeakPtrIS3_EEJRKiRKjS6_EEEvS8_OT_DpOT0_
#40 0x0000f24a4832 _ZN4base8internal12InvokeHelperILb1EvE8MakeItSoIRKMN4mojo13SimpleWatcherEFvijRKNS4_18HandleSignalsStateEERKNS_7WeakPtrIS5_EEJRKiRKjS8_EEEvOT_OT0_DpOT1_
#41 0x0000f24a4754 _ZN4base8internal7InvokerINS0_9BindStateIMN4mojo13SimpleWatcherEFvijRKNS3_18HandleSignalsStateEEJNS_7WeakPtrIS4_EEijS5_EEEFvvEE7RunImplIRKS9_RKNSt3__15tupleIJSB_ijS5_EEEJLj0ELj1ELj2ELj3EEEEvOT_OT0_NSI_16integer_sequenceIjJXspT1_EEEE
#42 0x0000f24a4531 _ZN4base8internal7InvokerINS0_9BindStateIMN4mojo13SimpleWatcherEFvijRKNS3_18HandleSignalsStateEEJNS_7WeakPtrIS4_EEijS5_EEEFvvEE3RunEPNS0_13BindStateBaseE
#43 0x0000f71e50e8 _ZNO4base12OnceCallbackIFvvEE3RunEv
#44 0x0000f7243698 base::debug::TaskAnnotator::RunTask()
#45 0x0000dfcd4ed4 blink::scheduler::TaskQueueManager::ProcessTaskFromWorkQueue()
#46 0x0000dfcd3ce6 blink::scheduler::TaskQueueManager::DoWork()
#47 0x0000df80344b _ZN4base8internal13FunctorTraitsIMN5blink26VideoFrameResourceProviderEFvPN3viz15ContextProviderEEvE6InvokeINS_7WeakPtrIS3_EEJS6_EEEvS8_OT_DpOT0_
#48 0x0000dfce84ba _ZN4base8internal12InvokeHelperILb1EvE8MakeItSoIRKMN5blink9scheduler16TaskQueueManagerEFvNS5_8internal8Sequence8WorkTypeEERKNS_7WeakPtrIS6_EEJRKS9_EEEvOT_OT0_DpOT1_
#49 0x0000dfce8418 _ZN4base8internal7InvokerINS0_9BindStateIMN5blink9scheduler16TaskQueueManagerEFvNS4_8internal8Sequence8WorkTypeEEJNS_7WeakPtrIS5_EES8_EEEFvvEE7RunImplIRKSA_RKNSt3__15tupleIJSC_S8_EEEJLj0ELj1EEEEvOT_OT0_NSJ_16integer_sequenceIjJXspT1_EEEE
#50 0x0000dfce82a1 _ZN4base8internal7InvokerINS0_9BindStateIMN5blink9scheduler16TaskQueueManagerEFvNS4_8internal8Sequence8WorkTypeEEJNS_7WeakPtrIS5_EES8_EEEFvvEE3RunEPNS0_13BindStateBaseE
#51 0x0000f71e50e8 _ZNO4base12OnceCallbackIFvvEE3RunEv
#52 0x0000f7243698 base::debug::TaskAnnotator::RunTask()
#53 0x0000dfcec030 blink::scheduler::internal::ThreadControllerImpl::DoWork()
#54 0x0000dfced82b _ZN4base8internal13FunctorTraitsIMN5blink9scheduler8internal20ThreadControllerImplEFvNS4_8Sequence8WorkTypeEEvE6InvokeIRKNS_7WeakPtrIS5_EEJRKS7_EEEvS9_OT_DpOT0_
#55 0x0000dfced76a _ZN4base8internal12InvokeHelperILb1EvE8MakeItSoIRKMN5blink9scheduler8internal20ThreadControllerImplEFvNS6_8Sequence8WorkTypeEERKNS_7WeakPtrIS7_EEJRKS9_EEEvOT_OT0_DpOT1_
#56 0x0000dfced6c8 _ZN4base8internal7InvokerINS0_9BindStateIMN5blink9scheduler8internal20ThreadControllerImplEFvNS5_8Sequence8WorkTypeEEJNS_7WeakPtrIS6_EES8_EEEFvvEE7RunImplIRKSA_RKNSt3__15tupleIJSC_S8_EEEJLj0ELj1EEEEvOT_OT0_NSJ_16integer_sequenceIjJXspT1_EEEE
#57 0x0000dfced551 _ZN4base8internal7InvokerINS0_9BindStateIMN5blink9scheduler8internal20ThreadControllerImplEFvNS5_8Sequence8WorkTypeEEJNS_7WeakPtrIS6_EES8_EEEFvvEE3RunEPNS0_13BindStateBaseE
#58 0x0000f71e50e8 _ZNO4base12OnceCallbackIFvvEE3RunEv
#59 0x0000f7243698 base::debug::TaskAnnotator::RunTask()
#60 0x0000f72f9e32 base::internal::IncomingTaskQueue::RunTask()
#61 0x0000f7304356 base::MessageLoop::RunTask()

Same stack as  issue 798476 , presumably the same cause.

 Issue 801655  has been merged into this issue.

It looks that an owner is assigned.

I got the same crash in a different test, in ContentSettingBubbleModelMixedScriptOopifTest.MixedContentInCrossSiteIframe. Link for the log in case there's something interesting there:
https://logs.chromium.org/v/?s=chromium%2Fbb%2Ftryserver.chromium.win%2Fwin7_chromium_rel_ng%2F80959%2F%2B%2Frecipes%2Fsteps%2Fbrowser_tests__with_patch_%2F0%2Flogs%2FContentSettingBubbleModelMixedScriptOopifTest.MixedContentInCrossSiteIframe%2F0

(CL: https://chromium-review.googlesource.com/c/chromium/src/+/861389)

Should be fixed by r530669, and I don't see any recent flakes for this test.