Test log from https://chromium-swarm.appspot.com/task?id=40f02082e3e88110:
[ RUN      ] SystemDisplayApiTest.SetDisplay

DevTools listening on ws://127.0.0.1:56257/devtools/browser/50b0d72f-8d10-4ca9-ab5b-98ef351c0f74
tracing_service_impl.cc( Producer 1 connected
tracing_service_impl.cc( Producer 1 disconnected
Received fatal exception EXCEPTION_ACCESS_VIOLATION
[5392:7124:1102/190348.416:8907969:WARNING:discardable_shared_memory_manager.cc(410)] Some MojoDiscardableSharedMemoryManagerImpls are still alive. They will be leaked.
Backtrace:
	perfetto::Producer::`vcall'{4}' [0x56A088DC+12]
	??$_Call@P8Producer@perfetto@@AEXXZAAPAV12@$$V@_Invoker_pmf_pointer@std@@SAXP8Producer@perfetto@@AEXXZAAPAV23@@Z [0x56A2CCD4+36]
	std::invoke<void (__thiscall perfetto::Producer::*&)(void),perfetto::Producer * &> [0x56A2CC7F+79]
	std::_Invoker_ret<std::_Unforced,0>::_Call<void (__thiscall perfetto::Producer::*&)(void),perfetto::Producer * &> [0x56A2CBAA+58]
	??$_Call_binder@U_Unforced@std@@$0A@P8Producer@perfetto@@AEXXZV?$tuple@PAVProducer@perfetto@@@2@V?$tuple@$$V@2@@std@@YAXU?$_Invoker_ret@U_Unforced@std@@$0A@@0@U?$integer_sequence@I$0A@@0@AAP8Producer@perfetto@@AEXXZAAV?$tuple@PAVProducer@perfetto@@@0@$$QA [0x56A2CB30+80]
	??$?R$$V@?$_Binder@U_Unforced@std@@P8Producer@perfetto@@AEXXZAAPAV34@@std@@QAEXXZ [0x56A2CACF+95]
	??$_Call@AAV?$_Binder@U_Unforced@std@@P8Producer@perfetto@@AEXXZAAPAV34@@std@@$$V@_Invoker_functor@std@@SAXAAV?$_Binder@U_Unforced@std@@P8Producer@perfetto@@AEXXZAAPAV34@@1@@Z [0x56A2CA5E+30]
	??$invoke@AAV?$_Binder@U_Unforced@std@@P8Producer@perfetto@@AEXXZAAPAV34@@std@@$$V@std@@YAXAAV?$_Binder@U_Unforced@std@@P8Producer@perfetto@@AEXXZAAPAV34@@0@@Z [0x56A2CA0F+31]
	std::_Invoker_ret<void,1>::_Call<std::_Binder<std::_Unforced,void (__thiscall perfetto::Producer::*)(void),perfetto::Producer * &> &> [0x56A2C9DF+31]
	?_Do_call@?$_Func_impl_no_alloc@V?$_Binder@U_Unforced@std@@P8Producer@perfetto@@AEXXZAAPAV34@@std@@X$$V@std@@EAEXXZ [0x56A2C717+23]
	??R?$_Func_class@X$$V@std@@QBEXXZ [0x56BD7151+65]
	std::forward<std::function<void __cdecl(void)> > [0x56BD70A6+54]
	std::forward<std::tuple<std::function<void __cdecl(void)> > > [0x56BD7054+132]
	std::move<std::tuple<std::function<void __cdecl(void)> > &> [0x56BD6F7A+122]
	std::forward<std::function<void __cdecl(void)> &> [0x56BD6EFA+138]
	perfetto::base::TaskRunner::`scalar deleting destructor' [0x56BD6DB4+116]
	base::OnceCallback<void __cdecl(void)>::Run [0x7270E830+80]
	base::debug::TaskAnnotator::RunTask [0x72771FD3+1075]
	base::internal::TaskTracker::RunOrSkipTask [0x729D6272+2690]
	base::internal::TaskTracker::RunAndPopNextTask [0x729D468E+638]
	base::internal::SchedulerWorker::RunWorker [0x729B49F3+2147]
	base::internal::SchedulerWorker::RunBackgroundDedicatedWorker [0x729B3FB2+34]
	base::internal::SchedulerWorker::ThreadMain [0x729B3E44+116]
	base::PlatformThread::GetDefaultThreadStackSize [0x729E8456+406]
	BaseThreadInitThunk [0x75C0337A+18]
	RtlInitializeExceptionChain [0x77B392B2+99]
	RtlInitializeExceptionChain [0x77B39285+54]
[1/1] SystemDisplayApiTest.SetDisplay (CRASHED)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9a651cb3874e3d7396428bce866f8e58779d9cd9

commit 9a651cb3874e3d7396428bce866f8e58779d9cd9
Author: Kunihiko Sakamoto <ksakamoto@chromium.org>
Date: Mon Nov 05 06:57:24 2018

Revert "Perfetto: Unify TraceEventAgent classes"

This reverts commit aa69df1c18ea91a85f04fe5ce881d894429d4edf.

Reason for revert: culprit for flakes of
- SystemDisplayApiTest.SetDisplay ( crbug.com/901586 ) and
- HeadlessBrowserTest.CreateAndDestroyBrowserContext ( crbug.com/901637 )

Original change's description:
> Perfetto: Unify TraceEventAgent classes
> 
> This unifies the Perfetto and non-Perfetto TraceEventAgent classes, so
> that it's possible to use Perfetto directly even when it's not enabled
> as the default TraceLog backend.
> 
> Also moved the Mojo bindings of ProducerHost into a StrongBindingSet of PerfettoService
> so they get cleaned up if the service gets shut down.
> 
> Already reviewed as part of https://chromium-review.googlesource.com/c/chromium/src/+/1161541
> 
> Change-Id: I3070d69e92778de8e3b5e33957ab4f4694b782af
> Reviewed-on: https://chromium-review.googlesource.com/c/1307998
> Commit-Queue: oysteine <oysteine@chromium.org>
> Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
> Reviewed-by: oysteine <oysteine@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#605060}

TBR=oysteine@chromium.org,skyostil@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.
Bug:  901586 , 901637 

Change-Id: I45f18d58e6355722c124ee753de5021e1d965da5
Reviewed-on: https://chromium-review.googlesource.com/c/1317298
Reviewed-by: Kunihiko Sakamoto <ksakamoto@chromium.org>
Commit-Queue: Kunihiko Sakamoto <ksakamoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#605268}
[modify] https://crrev.com/9a651cb3874e3d7396428bce866f8e58779d9cd9/services/tracing/coordinator.h
[modify] https://crrev.com/9a651cb3874e3d7396428bce866f8e58779d9cd9/services/tracing/perfetto/perfetto_service.cc
[modify] https://crrev.com/9a651cb3874e3d7396428bce866f8e58779d9cd9/services/tracing/perfetto/perfetto_service.h
[modify] https://crrev.com/9a651cb3874e3d7396428bce866f8e58779d9cd9/services/tracing/perfetto/producer_host.cc
[modify] https://crrev.com/9a651cb3874e3d7396428bce866f8e58779d9cd9/services/tracing/perfetto/producer_host.h
[modify] https://crrev.com/9a651cb3874e3d7396428bce866f8e58779d9cd9/services/tracing/perfetto/test_utils.cc
[modify] https://crrev.com/9a651cb3874e3d7396428bce866f8e58779d9cd9/services/tracing/perfetto/test_utils.h
[modify] https://crrev.com/9a651cb3874e3d7396428bce866f8e58779d9cd9/services/tracing/public/cpp/perfetto/producer_client.cc
[modify] https://crrev.com/9a651cb3874e3d7396428bce866f8e58779d9cd9/services/tracing/public/cpp/perfetto/producer_client.h
[modify] https://crrev.com/9a651cb3874e3d7396428bce866f8e58779d9cd9/services/tracing/public/cpp/perfetto/trace_event_data_source.cc
[modify] https://crrev.com/9a651cb3874e3d7396428bce866f8e58779d9cd9/services/tracing/public/cpp/perfetto/traced_value_proto_writer.cc
[modify] https://crrev.com/9a651cb3874e3d7396428bce866f8e58779d9cd9/services/tracing/public/cpp/perfetto/traced_value_proto_writer.h
[modify] https://crrev.com/9a651cb3874e3d7396428bce866f8e58779d9cd9/services/tracing/public/cpp/perfetto/traced_value_proto_writer_unittest.cc
[modify] https://crrev.com/9a651cb3874e3d7396428bce866f8e58779d9cd9/services/tracing/public/cpp/trace_event_agent.cc
[modify] https://crrev.com/9a651cb3874e3d7396428bce866f8e58779d9cd9/services/tracing/public/cpp/trace_event_agent.h
[modify] https://crrev.com/9a651cb3874e3d7396428bce866f8e58779d9cd9/services/tracing/public/cpp/trace_event_agent_unittest.cc
[modify] https://crrev.com/9a651cb3874e3d7396428bce866f8e58779d9cd9/services/tracing/tracing_service.cc