yesterday: https://logs.chromium.org/v/?s=chromium%2Fbb%2Ftryserver.chromium.linux%2Flinux_chromium_chromeos_rel_ng%2F531676%2F%2B%2Frecipes%2Fsteps%2Fmus_browser_tests__with_patch_%2F0%2Flogs%2FWebViewTests__x2f_WebViewTest.NestedGuestContainerBounds__x2f_1%2F0

today: https://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_chromeos_rel_ng/builds/532819


[32724:32759:1018/110842.989057:FATAL:optional.h(177)] Check failed: !storage_.is_null_.
#0 0x000003aa0e3c base::debug::StackTrace::StackTrace()
#1 0x000003abaccc logging::LogMessage::~LogMessage()
#2 0x000000d282aa base::Optional<>::operator->()
#3 0x00000586f294 viz::SurfaceAggregator::PrewalkTree()
#4 0x000005870652 viz::SurfaceAggregator::PrewalkTree()
#5 0x000005870652 viz::SurfaceAggregator::PrewalkTree()
#6 0x000005870652 viz::SurfaceAggregator::PrewalkTree()
#7 0x0000058715bd viz::SurfaceAggregator::Aggregate()
#8 0x000005846c01 viz::Display::DrawAndSwap()
#9 0x00000584913a viz::DisplayScheduler::DrawAndSwap()
#10 0x00000584880b viz::DisplayScheduler::AttemptDrawAndSwap()
#11 0x0000058481d6 viz::DisplayScheduler::OnBeginFrameDeadline()
#12 0x0000006bd837 _ZN4base8internal7InvokerINS0_9BindStateIMN12_GLOBAL__N_116SimpleHttpServer10ConnectionEFvvEJNS_7WeakPtrIS5_EEEEEFvvEE7RunOnceEPNS0_13BindStateBaseE
#13 0x0000006e59c1 base::CancelableCallback<>::Forward()
#14 0x0000006bd837 _ZN4base8internal7InvokerINS0_9BindStateIMN12_GLOBAL__N_116SimpleHttpServer10ConnectionEFvvEJNS_7WeakPtrIS5_EEEEEFvvEE7RunOnceEPNS0_13BindStateBaseE
#15 0x000003aa1605 base::debug::TaskAnnotator::RunTask()
#16 0x000003b56819 base::internal::IncomingTaskQueue::RunTask()
#17 0x000003ac2928 base::MessageLoop::RunTask()
#18 0x000003ac2c4a base::MessageLoop::DeferOrRunPendingTask()
#19 0x000003ac31c8 base::MessageLoop::DoDelayedWork()
#20 0x000003ac407d base::MessagePumpDefault::Run()
#21 0x000003ac2312 base::MessageLoop::Run()
#22 0x000003aeba5f base::RunLoop::Run()
#23 0x000003b19447 base::Thread::Run()
#24 0x000003b199fc base::Thread::ThreadMain()
#25 0x000003b1217f base::(anonymous namespace)::ThreadFunc()
#26 0x7fd5eb752184 start_thread
#27 0x7fd5e8451ffd clone