Chrome ToT r455790 on linux desktop, chromeos=1 ozone build

Send SIGTERM to chrome --mash root process (e.g. "kill <pid>"). This triggers a clean shutdown of the root, which tears down the mojo service manager which should terminate all child services.

[11175:11175:0309/135458.492005:FATAL:context_provider_command_buffer.cc(178)] Check failed: channel_. 
#0 0x7fd48184b397 base::debug::StackTrace::StackTrace()
#1 0x7fd48186ce5a logging::LogMessage::~LogMessage()
#2 0x7fd47f56612e ui::ContextProviderCommandBuffer::ContextProviderCommandBuffer()
#3 0x7fd47f568836 ui::Gpu::CreateContextProvider()
#4 0x7fd47f6e05db content::RenderThreadImpl::CreateCompositorFrameSink()
#5 0x7fd47f6fd7fe content::RenderWidget::CreateCompositorFrameSink()
#6 0x7fd47f6fd8a0 content::RenderWidget::CreateCompositorFrameSink()
#7 0x7fd47f6508c0 content::RenderWidgetCompositor::RequestNewCompositorFrameSink()
#8 0x7fd47def353b cc::ProxyMain::RequestNewCompositorFrameSink()
#9 0x7fd47ddb524b _ZN4base8internal13FunctorTraitsIMN2cc28ScrollbarAnimationControllerEFvvEvE6InvokeIRKNS_7WeakPtrIS3_EEJEEEvS5_OT_DpOT0_
#10 0x7fd48184be59 base::debug::TaskAnnotator::RunTask()
#11 0x7fd47aee9c50 blink::scheduler::TaskQueueManager::ProcessTaskFromWorkQueue()
#12 0x7fd47aee7390 blink::scheduler::TaskQueueManager::DoWork()
#13 0x7fd47aeebfc2 _ZN4base8internal13FunctorTraitsIMN5blink9scheduler16TaskQueueManagerEFvbEvE6InvokeIRKNS_7WeakPtrIS4_EEJRKbEEEvS6_OT_DpOT0_
#14 0x7fd48184be59 base::debug::TaskAnnotator::RunTask()
#15 0x7fd481879c3d base::MessageLoop::RunTask()
#16 0x7fd48187a305 base::MessageLoop::DoWork()
#17 0x7fd48187bb29 base::MessagePumpDefault::Run()
#18 0x7fd4818799ba base::MessageLoop::RunHandler()
#19 0x7fd4818ac53f base::RunLoop::Run()
#20 0x7fd47f70a7ae content::RendererMain()
#21 0x7fd47f8582f7 content::RunZygote()
#22 0x7fd47f85946c content::ContentMainRunnerImpl::Run()
#23 0x7fd47f857c20 content::ContentMain()
#24 0x7fd4824648a0 ChromeMain
#25 0x7fd4788f4f45 __libc_start_main
#26 0x7fd4824646fd <unknown>

This DCHECK is interfering with my ability to diagnose some shutdown hangs, but it looks like it might be a real problem.

Sadrul, any idea what's going on here?