Run a test that uses NetworkServiceTestHelper (Like CommonNameMismatchBrowserTest.WWWSubdomainMismatch_StopOnRedirects/0) with --enable-features=NetworkService, and the test passes, but the NetworkService crashes when it's being torn down.  It looks like a DCHECK that the helper's binding is being torn down on the correct thread fails (Maybe it's outliving the message loop?  Not sure).

This seems less than ideal, particularly as the crash pops up a modal dialog about the crash on Windows.  Not sure if this affects other platforms, but I'd assume it does.  Ran into this when converting a test to use the test infrastructure, and a bit worried about the conversion running into issues on bots, though suppose only the Linux bots really have any prominence, currently.

Sample trace:

[6932:39432:0524/153747.359:FATAL:interface_endpoint_client.cc(170)] Check failed: (sequence_checker_).CalledOnValidSequence().
Backtrace:
base::debug::StackTrace::StackTrace [0x00007FFAFCC9F725+101] (C:\src\chrome\src\base\debug\stack_trace_win.cc:286)
base::debug::StackTrace::StackTrace [0x00007FFAFCC9E75F+31] (C:\src\chrome\src\base\debug\stack_trace.cc:199)
logging::LogMessage::~LogMessage [0x00007FFAFCCFFEB6+134] (C:\src\chrome\src\base\logging.cc:593)
mojo::InterfaceEndpointClient::~InterfaceEndpointClient [0x00007FFB16391A05+197] (C:\src\chrome\src\mojo\public\cpp\bindings\lib\interface_endpoint_client.cc:171)
mojo::InterfaceEndpointClient::~InterfaceEndpointClient [0x00007FFB1639442C+44] (C:\src\chrome\src\mojo\public\cpp\bindings\lib\interface_endpoint_client.cc:169)
std::default_delete<mojo::InterfaceEndpointClient>::operator() [0x00007FFB1637288F+63] (C:\src\chrome\src\third_party\depot_tools\win_toolchain\vs_files\5454e45bf3764c03d3fc1024b3bf5bc41e3ab62c\VC\Tools\MSVC\14.14.26428\include\memory:2055)
std::unique_ptr<mojo::InterfaceEndpointClient,std::default_delete<mojo::InterfaceEndpointClient> >::reset [0x00007FFB16371D54+100] (C:\src\chrome\src\third_party\depot_tools\win_toolchain\vs_files\5454e45bf3764c03d3fc1024b3bf5bc41e3ab62c\VC\Tools\MSVC\14.14.26428\include\memory:2306)
mojo::internal::BindingStateBase::Close [0x00007FFB1637A0A7+55] (C:\src\chrome\src\mojo\public\cpp\bindings\lib\binding_state.cc:45)
mojo::internal::BindingState<network::mojom::NetworkServiceTest,mojo::RawPtrImplRefTraits<network::mojom::NetworkServiceTest> >::~BindingState [0x00007FF6ED5BD63F+31] (C:\src\chrome\src\mojo\public\cpp\bindings\lib\binding_state.h:108)
mojo::Binding<network::mojom::NetworkServiceTest,mojo::RawPtrImplRefTraits<network::mojom::NetworkServiceTest> >::~Binding [0x00007FF6ED5BD613+19] (C:\src\chrome\src\mojo\public\cpp\bindings\binding.h:94)

<SNIP>

mojo::BindingSetBase<network::mojom::NetworkServiceTest,mojo::Binding<network::mojom::NetworkServiceTest,mojo::RawPtrImplRefTraits<network::mojom::NetworkServiceTest> >,void>::~BindingSetBase [0x00007FF6ED5BC773+51] (C:\src\chrome\src\mojo\public\cpp\bindings\binding_set.h:64)
content::NetworkServiceTestHelper::NetworkServiceTestImpl::~NetworkServiceTestImpl [0x00007FF6ED5BC727+87] (C:\src\chrome\src\content\public\test\network_service_test_helper.cc:53)
content::NetworkServiceTestHelper::NetworkServiceTestImpl::~NetworkServiceTestImpl [0x00007FF6ED5BBADC+44] (C:\src\chrome\src\content\public\test\network_service_test_helper.cc:51)