cast_shell_browsertests failing on chromium.linux/Cast Linux

Builders failed on: 
- Cast Linux: 
  https://build.chromium.org/p/chromium.linux/builders/Cast%20Linux

CastNavigationBrowserTest.AudioPlaybackWavPcm failed while I'm sheriffing. No CL looks responsible. The crash seems like we may be handling errors on the wrong thread or something.

[14022:14022:WARNING:pref_notifier_impl.cc(23)] Pref observer found at shutdown.
BrowserTestBase received signal: Segmentation fault. Backtrace:
#0 0x000001493547 base::debug::StackTrace::StackTrace()
#1 0x0000032d07c6 content::(anonymous namespace)::DumpStackTraceSignalHandler()
#2 0x7f98e6014d40 <unknown>
#3 0x00000071b133 chromecast::media::MediaPipelineImpl::~MediaPipelineImpl()
#4 0x00000071f8c0 chromecast::media::CastRenderer::~CastRenderer()
#5 0x00000071f9e9 chromecast::media::CastRenderer::~CastRenderer()
#6 0x00000072a424 media::MojoRendererService::~MojoRendererService()
#7 0x00000072a559 media::MojoRendererService::~MojoRendererService()
#8 0x000000721bd4 std::_Rb_tree<>::_M_erase()
#9 0x0000007211eb media::InterfaceFactoryImpl::~InterfaceFactoryImpl()
#10 0x000000721239 media::InterfaceFactoryImpl::~InterfaceFactoryImpl()
#11 0x000000724425 mojo::BindingSetBase<>::OnConnectionError()
#12 0x00000152b6ee mojo::InterfaceEndpointClient::NotifyError()
#13 0x00000152fcf3 mojo::internal::MultiplexRouter::ProcessNotifyErrorTask()
#14 0x00000152e9c2 mojo::internal::MultiplexRouter::ProcessTasks()
#15 0x00000152d628 mojo::internal::MultiplexRouter::OnPipeConnectionError()
#16 0x000001529882 mojo::Connector::HandleError()
#17 0x00000153689a mojo::SimpleWatcher::OnHandleReady()
#18 0x00000150a150 base::debug::TaskAnnotator::RunTask()
#19 0x0000014a8a4d base::MessageLoop::RunTask()
#20 0x0000014a8d98 base::MessageLoop::DeferOrRunPendingTask()
#21 0x0000014a9171 base::MessageLoop::DoWork()
#22 0x0000014aa06a base::MessagePumpDefault::Run()
#23 0x0000014c2bbe base::RunLoop::Run()
#24 0x0000014e1b15 base::Thread::ThreadMain()
#25 0x0000014dd3f3 base::(anonymous namespace)::ThreadFunc()
#26 0x7f98e8fe8182 start_thread
#27 0x7f98e60d847d clone
[21/21] CastNavigationBrowserTest.AudioPlaybackWavPcm (1569 ms)