WindowTreeClientTest.EmbedFailsFromOtherConnection is crashing during teardown on win8_chromium_ng. For example (from https://build.chromium.org/p/tryserver.chromium.win/builders/win8_chromium_ng/builds/123900/steps/mus_ws_unittests%20%28with%20patch%29/logs/stdio):

[ RUN      ] WindowTreeClientTest.EmbedFailsFromOtherConnection

[3044:4052:0329/161838:2518781:ERROR:shell.cc(363)] Capabilities prevented connection from: mojo:resource_provider to: mojo:tracing

Backtrace:

	base::ObserverListBase<base::MessageLoop::TaskObserver>::AddObserver [0x018875A8+88]

	base::MessageLoop::AddDestructionObserver [0x0181F292+98]

	mojo::internal::SyncHandleRegistry::SyncHandleRegistry [0x00E69F2E+342]

	mojo::internal::SyncHandleRegistry::current [0x00E6A537+56]

	mojo::internal::SyncHandleWatcher::~SyncHandleWatcher [0x00E6A78A+96]

	std::default_delete<mojo::internal::SyncHandleWatcher>::operator() [0x00E61545+17]

	mojo::internal::Connector::CancelWait [0x00E6175D+30]

	mojo::internal::Connector::CloseMessagePipe [0x00E617B9+91]

	mojo::internal::MultiplexRouter::CloseMessagePipe [0x00E65FF7+97]

	mojo::internal::BindingState<mus::mojom::WindowTreeClient,1>::Close [0x00CDE4CD+104]

	mojo::internal::BindingState<mus::mojom::WindowTreeClient,1>::~BindingState<mus::mojom::WindowTreeClient,1> [0x00CDDF1E+13]

	mojo::AssociatedBinding<mus::mojom::WindowManager>::~AssociatedBinding<mus::mojom::WindowManager> [0x00CEEB51+89]

	mus::ws::test::`anonymous namespace'::TestWindowTreeClientImpl::`scalar deleting destructor' [0x00CEEDE7+11]

	mojo::AssociatedBinding<mus::mojom::WindowManager>::~AssociatedBinding<mus::mojom::WindowManager> [0x00CEEBBA+194]

	mus::ws::test::`anonymous namespace'::WindowTreeClientFactory::`scalar deleting destructor' [0x00CEEE06+11]

	mus::ws::test::WindowTreeClientTest::~WindowTreeClientTest [0x00CEEBDB+25]

	mus::ws::test::WindowTreeClientTest_WindowsRemovedWhenEmbedding_Test::`scalar deleting destructor' [0x00CEEE25+11]

	mojo::edk::RemoteMessagePipeBootstrap::ShutDownNow [0x017A134B+10]

	testing::internal::HandleExceptionsInMethodIfSupported<testing::TestCase,void> [0x018A2BCD+32]

	testing::TestInfo::Run [0x018AB715+156]

	testing::TestCase::Run [0x018AB622+133]

	testing::internal::UnitTestImpl::RunAllTests [0x018AB9A2+434]

	testing::internal::HandleExceptionsInMethodIfSupported<testing::internal::UnitTestImpl,bool> [0x018A2C11+32]

	testing::UnitTest::Run [0x018AB7CB+133]

	base::TestSuite::Run [0x00D2B4F8+143]

	base::LaunchUnitTests [0x00D3906E+785]

	base::LaunchUnitTests [0x00D38D49+68]

	MasterProcessMain [0x00E71336+71]

	main [0x0181CD38+103]

	__scrt_common_main_seh [0x01AED170+255] (f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:264)

	BaseThreadInitThunk [0x76BC919F+14]

	RtlInitializeExceptionChain [0x7715AD1F+143]

	RtlInitializeExceptionChain [0x7715ACEA+90]

[68/135] WindowTreeClientTest.EmbedFailsFromOtherConnection (CRASHED)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e520a87d9f58e2fbd58a926bbea2cfc68a7dc3c9

commit e520a87d9f58e2fbd58a926bbea2cfc68a7dc3c9
Author: grt <grt@chromium.org>
Date: Wed Mar 30 15:08:53 2016

Disable WindowTreeClientTest.EmbedFailsFromOtherConnection on win due to flakes.

BUG= 598925 
TBR=sky@chromium.org

Review URL: https://codereview.chromium.org/1847553002

Cr-Commit-Position: refs/heads/master@{#383981}

[modify] https://crrev.com/e520a87d9f58e2fbd58a926bbea2cfc68a7dc3c9/components/mus/ws/window_tree_client_unittest.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e520a87d9f58e2fbd58a926bbea2cfc68a7dc3c9

commit e520a87d9f58e2fbd58a926bbea2cfc68a7dc3c9
Author: grt <grt@chromium.org>
Date: Wed Mar 30 15:08:53 2016

Disable WindowTreeClientTest.EmbedFailsFromOtherConnection on win due to flakes.

BUG= 598925 
TBR=sky@chromium.org

Review URL: https://codereview.chromium.org/1847553002

Cr-Commit-Position: refs/heads/master@{#383981}

[modify] https://crrev.com/e520a87d9f58e2fbd58a926bbea2cfc68a7dc3c9/components/mus/ws/window_tree_client_unittest.cc

Detected 3 new flakes for test/step "mus_ws_unittests (with patch)". To see the actual flakes, please visit https://chromium-try-flakes.appspot.com/all_flake_occurrences?key=ahVzfmNocm9taXVtLXRyeS1mbGFrZXNyKAsSBUZsYWtlIh1tdXNfd3NfdW5pdHRlc3RzICh3aXRoIHBhdGNoKQw. This message was posted automatically by the chromium-try-flakes app. Since flakiness is ongoing, the issue was moved back into Sheriff Bug Queue (unless already there).

Hmm, I think WindowsRemovedWhenEmbedding is the real problem. Disabling that and re-enabling EmbedFailsFromOtherConnection.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/74e479e3cfe8b54d3aa0d0bfef81a6786b47d2c8

commit 74e479e3cfe8b54d3aa0d0bfef81a6786b47d2c8
Author: grt <grt@chromium.org>
Date: Thu Mar 31 14:30:17 2016

Disable WindowTreeClientTest.WindowsRemovedWhenEmbedding on win due to flakes.

Re-enabled EmbedFailsFromOtherConnection since that seems to have been a
red herring.

BUG= 598925 
TBR=sky@chromium.org

Review URL: https://codereview.chromium.org/1848693004

Cr-Commit-Position: refs/heads/master@{#384271}

[modify] https://crrev.com/74e479e3cfe8b54d3aa0d0bfef81a6786b47d2c8/components/mus/ws/window_tree_client_unittest.cc

Detected 4 new flakes for test/step "mus_ws_unittests (with patch)". To see the actual flakes, please visit https://chromium-try-flakes.appspot.com/all_flake_occurrences?key=ahVzfmNocm9taXVtLXRyeS1mbGFrZXNyKAsSBUZsYWtlIh1tdXNfd3NfdW5pdHRlc3RzICh3aXRoIHBhdGNoKQw. This message was posted automatically by the chromium-try-flakes app. Since flakiness is ongoing, the issue was moved back into Sheriff Bug Queue (unless already there).

Thanks for being on top of this sky@ - I'll remove this from the sheriffs' queue (please shout if this is wrong / if I should help with tracking this down and/or with disabling the test).

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b96ea97ff5ff29c43314f5925fa37321149725bb

commit b96ea97ff5ff29c43314f5925fa37321149725bb
Author: sky <sky@chromium.org>
Date: Fri Apr 01 20:21:59 2016

Makes WindowTreeClientTest destroy state in TearDown

Problem with waiting for destructor is at that point the MessageLoop has been destroyed, which causes problems with binding code.

BUG= 598925 
TEST=test only change
R=ben@chromium.org

Review URL: https://codereview.chromium.org/1843333005

Cr-Commit-Position: refs/heads/master@{#384676}

[modify] https://crrev.com/b96ea97ff5ff29c43314f5925fa37321149725bb/components/mus/ws/window_tree_client_unittest.cc