Example Stack Trace:

[ RUN      ] PPAPINaClGLibcTest.TCPSocket_Connect
[18849:2819:0831/132046.236111:WARNING:notification_platform_bridge_mac.mm(510)] AlertNotificationService: XPC connection invalidated.
[18858:775:0831/132046.617308:WARNING:vt_video_decode_accelerator_mac.cc(193)] Failed to create VTDecompressionSession: Error Domain=NSOSStatusErrorDomain Code=-8973 "codecOpenErr" (-8973)
[18858:775:0831/132046.618184:WARNING:vt_video_decode_accelerator_mac.cc(215)] Hardware decoding with VideoToolbox is not supported
[18858:775:0831/132046.713144:ERROR:vt_video_encode_accelerator_mac.cc(512)]  VTCompressionSessionCreate failed: -12908
[18849:775:0831/132047.021913:ERROR:delegated_frame_host.cc(173)] Not implemented reached in void content::DelegatedFrameHost::SetNeedsBeginFrames(bool)
[18849:775:0831/132047.677635:WARNING:gaia_auth_fetcher.cc(982)] Could not reach Google Accounts servers: errno -11
[18849:775:0831/132048.702950:WARNING:gaia_auth_fetcher.cc(982)] Could not reach Google Accounts servers: errno -11
[18849:129291:0831/132049.542521:WARNING:embedded_test_server.cc(238)] Request not handled. Returning 404: /favicon.ico
[18881,2938446720:13:20:49.967009] Native Client module will be loaded at base address 0x00003bec00000000
[18849:775:0831/132051.683903:WARNING:gaia_auth_fetcher.cc(982)] Could not reach Google Accounts servers: errno -11
[18849:775:0831/132058.908663:WARNING:gaia_auth_fetcher.cc(982)] Could not reach Google Accounts servers: errno -11
[18849:775:0831/132117.185306:INFO:CONSOLE(176)] "ConnectForceAsync finished in 26.020 seconds.", source: http://127.0.0.1:54667/test_case.html?mode=nacl_glibc&testcase=TCPSocket_Connect, (176)
[18849:775:0831/132122.163804:WARNING:gaia_auth_fetcher.cc(982)] Could not reach Google Accounts servers: errno -11
BrowserTestBase received signal: Terminated: 15. Backtrace:
0   libbase.dylib                       0x0000000128bb13be base::debug::StackTrace::StackTrace(unsigned long) + 174
1   libbase.dylib                       0x0000000128bb147d base::debug::StackTrace::StackTrace(unsigned long) + 29
2   libbase.dylib                       0x0000000128799afc base::debug::StackTrace::StackTrace() + 28
3   browser_tests                       0x000000010e32e7de content::(anonymous namespace)::DumpStackTraceSignalHandler(int) + 622
4   libsystem_platform.dylib            0x00007fff76d4ef5a _sigtramp + 26
5   libbase.dylib                       0x0000000128c40d40 vtable for base::Histogram + 16
6   CoreFoundation                      0x00007fff4eb9b045 __CFRunLoopServiceMachPort + 341
7   CoreFoundation                      0x00007fff4eb9a397 __CFRunLoopRun + 1783
8   CoreFoundation                      0x00007fff4eb99a07 CFRunLoopRunSpecific + 487
9   HIToolbox                           0x00007fff4de75d96 RunCurrentEventLoopInMode + 286
10  HIToolbox                           0x00007fff4de75b06 ReceiveNextEventCommon + 613
11  HIToolbox                           0x00007fff4de75884 _BlockUntilNextEventMatchingListInModeWithFilter + 64
12  AppKit                              0x00007fff4c127a73 _DPSNextEvent + 2085
13  AppKit                              0x00007fff4c8bde34 -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 3044
14  browser_tests                       0x000000010c7eafba __71-[BrowserCrApplication nextEventMatchingMask:untilDate:inMode:dequeue:]_block_invoke + 106
15  libbase.dylib                       0x000000012880c14a base::mac::CallWithEHFrame(void () block_pointer) + 10
16  browser_tests                       0x000000010c7eae58 -[BrowserCrApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 248
17  AppKit                              0x00007fff4c11c885 -[NSApplication run] + 764
18  libbase.dylib                       0x000000012886976c base::MessagePumpNSApplication::DoRun(base::MessagePump::Delegate*) + 348
19  libbase.dylib                       0x00000001288665c5 base::MessagePumpCFRunLoopBase::Run(base::MessagePump::Delegate*) + 101
20  libbase.dylib                       0x000000012885867c base::MessageLoop::Run(bool) + 556
21  libbase.dylib                       0x0000000128943c7e base::RunLoop::Run() + 606
22  browser_tests                       0x000000010e41a9ec content::RunThisRunLoop(base::RunLoop*) + 44
23  browser_tests                       0x000000010e41a983 content::RunMessageLoop() + 51
24  browser_tests                       0x000000010e376236 content::JavascriptTestObserver::Run() + 198
25  browser_tests                       0x000000010c5cdbee PPAPITestBase::RunTestURL(GURL const&) + 174
26  browser_tests                       0x000000010c5ce676 PPAPITestBase::RunTestViaHTTP(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) + 1542
27  browser_tests                       0x000000010c5d1928 PPAPINaClTest::RunTestViaHTTP(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) + 40
28  browser_tests                       0x000000010802648f PPAPINaClGLibcTest_TCPSocket_Connect_Test::RunTestOnMainThread() + 223
29  browser_tests                       0x000000010e32cc74 content::BrowserTestBase::ProxyRunTestOnMainThreadLoop() + 2116
30  browser_tests                       0x000000010e32f8cd void base::internal::FunctorTraits<void (content::BrowserTestBase::*)(), void>::Invoke<void (content::BrowserTestBase::*)(), content::BrowserTestBase*>(void (content::BrowserTestBase::*)(), content::BrowserTestBase*&&) + 125
31  browser_tests                       0x000000010e32f814 void base::internal::InvokeHelper<false, void>::MakeItSo<void (content::BrowserTestBase::* const&)(), content::BrowserTestBase*>(void (content::BrowserTestBase::* const&&&)(), content::BrowserTestBase*&&) + 68
32  browser_tests                       0x000000010e32f7a3 void base::internal::Invoker<base::internal::BindState<void (content::BrowserTestBase::*)(), base::internal::UnretainedWrapper<content::BrowserTestBase> >, void ()>::RunImpl<void (content::BrowserTestBase::* const&)(), std::__1::tuple<base::internal::UnretainedWrapper<content::BrowserTestBase> > const&, 0ul>(void (content::BrowserTestBase::* const&&&)(), std::__1::tuple<base::internal::UnretainedWrapper<content::BrowserTestBase> > const&&&, std::__1::integer_sequence<unsigned long, 0ul>) + 99
33  browser_tests                       0x000000010e32f6cc base::internal::Invoker<base::internal::BindState<void (content::BrowserTestBase::*)(), base::internal::UnretainedWrapper<content::BrowserTestBase> >, void ()>::Run(base::internal::BindStateBase*) + 44
34  browser_tests                       0x00000001064a5ded base::RepeatingCallback<void ()>::Run() const & + 61
35  browser_tests                       0x000000010c7fcbb2 ChromeBrowserMainParts::PreMainMessageLoopRunImpl() + 8594
36  browser_tests                       0x000000010c7fa96a ChromeBrowserMainParts::PreMainMessageLoopRun() + 250
37  libcontent.dylib                    0x00000001368ebb71 content::BrowserMainLoop::PreMainMessageLoopRun() + 337
38  libcontent.dylib                    0x00000001368f246d int base::internal::FunctorTraits<int (content::BrowserMainLoop::*)(), void>::Invoke<int (content::BrowserMainLoop::*)(), content::BrowserMainLoop*>(int (content::BrowserMainLoop::*)(), content::BrowserMainLoop*&&) + 125
39  libcontent.dylib                    0x00000001368f23b4 int base::internal::InvokeHelper<false, int>::MakeItSo<int (content::BrowserMainLoop::* const&)(), content::BrowserMainLoop*>(int (content::BrowserMainLoop::* const&&&)(), content::BrowserMainLoop*&&) + 68
40  libcontent.dylib                    0x00000001368f2343 int base::internal::Invoker<base::internal::BindState<int (content::BrowserMainLoop::*)(), base::internal::UnretainedWrapper<content::BrowserMainLoop> >, int ()>::RunImpl<int (content::BrowserMainLoop::* const&)(), std::__1::tuple<base::internal::UnretainedWrapper<content::BrowserMainLoop> > const&, 0ul>(int (content::BrowserMainLoop::* const&&&)(), std::__1::tuple<base::internal::UnretainedWrapper<content::BrowserMainLoop> > const&&&, std::__1::integer_sequence<unsigned long, 0ul>) + 99
41  libcontent.dylib                    0x00000001368f223c base::internal::Invoker<base::internal::BindState<int (content::BrowserMainLoop::*)(), base::internal::UnretainedWrapper<content::BrowserMainLoop> >, int ()>::Run(base::internal::BindStateBase*) + 44
42  libcontent.dylib                    0x00000001374ee7dd base::RepeatingCallback<int ()>::Run() const & + 61
43  libcontent.dylib                    0x0000000137f452c0 content::StartupTaskRunner::RunAllTasksNow() + 528
44  libcontent.dylib                    0x00000001368e6c81 content::BrowserMainLoop::CreateStartupTasks() + 2769
45  libcontent.dylib                    0x00000001368f61de content::BrowserMainRunnerImpl::Initialize(content::MainFunctionParams const&) + 2430
46  libcontent.dylib                    0x00000001368de186 content::BrowserMain(content::MainFunctionParams const&) + 550
47  libcontent.dylib                    0x0000000139968015 content::RunBrowserProcessMain(content::MainFunctionParams const&, content::ContentMainDelegate*) + 309
48  libcontent.dylib                    0x000000013996b47e content::ContentMainRunnerImpl::Run(bool) + 4318
49  libcontent.dylib                    0x000000013996207c content::ContentServiceManagerMainDelegate::RunEmbedderProcess() + 76
50  libembedder.dylib                   0x000000014b0a63d9 service_manager::Main(service_manager::MainParams const&) + 3753
51  libcontent.dylib                    0x0000000139967e99 content::ContentMain(content::ContentMainParams const&) + 89
52  browser_tests                       0x000000010e32c0b1 content::BrowserTestBase::SetUp() + 8385
53  browser_tests                       0x000000010c5a99e5 InProcessBrowserTest::SetUp() + 3365
54  browser_tests                       0x000000010c5cceeb PPAPITestBase::SetUp() + 43
55  browser_tests                       0x000000010955e84e void testing::internal::HandleSehExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) + 126
56  browser_tests                       0x0000000109530862 void testing::internal::HandleExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) + 114
57  browser_tests                       0x0000000109530744 testing::Test::Run() + 116
58  browser_tests                       0x0000000109531755 testing::TestInfo::Run() + 213
59  browser_tests                       0x0000000109532b2f testing::TestCase::Run() + 239
60  browser_tests                       0x00000001095488c6 testing::internal::UnitTestImpl::RunAllTests() + 886
61  browser_tests                       0x00000001095617ee bool testing::internal::HandleSehExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) + 126

Reverting culprit r588092 in https://crrev.com/c/1201846; adding original CL author.

mmenke@, please take a look.

Culprit CL was already reverted in r588333.

Looks like the trbots on OSX aren't running browser_tests, or didn't on the original CL, and the OSX TCP/IP stack has some deviations from other platforms.  :(