Debug build, target_os=chromeos, on linux.

* Run chrome --mash
* Open task manager (shift-esc)
* Hit Ctrl-Q twice to exit

[78612:78612:1116/174146.643926:FATAL:single_thread_task_graph_runner.cc(38)] Check failed: !work_queue_.HasAnyNamespaces(). 
#0 0x7f09ba5f48ad base::debug::StackTrace::StackTrace()
#1 0x7f09ba5f2e2c base::debug::StackTrace::StackTrace()
#2 0x7f09ba677b6d logging::LogMessage::~LogMessage()
#3 0x7f09b1e89cb8 cc::SingleThreadTaskGraphRunner::Shutdown()
#4 0x7f09b001a537 ui::RasterThreadHelper::~RasterThreadHelper()
#5 0x7f09afc70fb1 aura::MusContextFactory::~MusContextFactory()
#6 0x7f09afc70fe9 aura::MusContextFactory::~MusContextFactory()
#7 0x7f09afca4324 aura::WindowTreeClient::~WindowTreeClient()
#8 0x7f09afca4bf9 aura::WindowTreeClient::~WindowTreeClient()
#9 0x7f09aa2fabac views::MusClient::~MusClient()
#10 0x7f09aa2fb5b9 views::MusClient::~MusClient()
#11 0x55a191c62970 ChromeBrowserMainExtraPartsViews::~ChromeBrowserMainExtraPartsViews()
#12 0x55a191c62d39 ChromeBrowserMainExtraPartsViews::~ChromeBrowserMainExtraPartsViews()
#13 0x55a18d88721f ChromeBrowserMainParts::~ChromeBrowserMainParts()
#14 0x55a18d891d05 ChromeBrowserMainPartsPosix::~ChromeBrowserMainPartsPosix()
#15 0x55a18d891ba5 ChromeBrowserMainPartsLinux::~ChromeBrowserMainPartsLinux()
#16 0x55a18c9e5d23 chromeos::ChromeBrowserMainPartsChromeos::~ChromeBrowserMainPartsChromeos()
#17 0x55a18c9e5d49 chromeos::ChromeBrowserMainPartsChromeos::~ChromeBrowserMainPartsChromeos()
#18 0x7f09b3d0c1d5 content::BrowserMainLoop::~BrowserMainLoop()
#19 0x7f09b3d0ca99 content::BrowserMainLoop::~BrowserMainLoop()
#20 0x7f09b3d2216c content::BrowserMainRunnerImpl::Shutdown()
#21 0x7f09b3d096d7 content::BrowserMain()
#22 0x7f09b5b12bed content::RunNamedProcessTypeMain()
#23 0x7f09b5b15692 content::ContentMainRunnerImpl::Run()
#24 0x7f09b5b0be0d content::ContentServiceManagerMainDelegate::RunEmbedderProcess()
#25 0x7f09bae74924 service_manager::Main()
#26 0x7f09b5b11b1b content::ContentMain()
#27 0x55a18af0c17f ChromeMain
#28 0x55a18af0c022 main
#29 0x7f099dc4df45 __libc_start_main
#30 0x55a18af0befa _start

This crash also happens frequently in mash browser tests, for example:
browser_tests --mash --gtest_filter=TaskManagerBrowserTest.*

It doesn't happen with --mus.

Fady/Sadrul/Scott - ideas?