The test started failing today:
https://build.chromium.org/p/chromium.fyi/builders/Chromium%20Mac%2010.11%20Force%20Mac%20Toolchain
"""
Dec 15 08:36	1e385fa1c19d96f343594a0623a7985adb50c483	failure	#14945
Failed steps failed browser_tests failed sync_integration_tests
Dec 15 05:22	12848de612f70226c03762ae1b7e4bcbc6d2b4a4	failure	#14944
Failed steps failed browser_tests failed sync_integration_tests
Dec 15 02:23	6582b2990f67141a85af1b2a4691598888bc03b7	failure	#14943
Failed steps failed browser_tests
"""

Looks like the test is timing out.
"""
[ RUN      ] TwoClientUssSyncTest.DisableEnable
2016-12-15 11:36:23.772 sync_integration_tests[76384:923787] NSWindow warning: adding an unknown subview: <FullSizeContentView: 0x7f92a98ae750>. Break on NSLog to debug.
2016-12-15 11:36:23.772 sync_integration_tests[76384:923787] Call stack:
(
    "+callStackSymbols disabled for performance reasons"
)
[76384:107271:1215/113624.552771:WARNING:server_connection_manager.cc(269)] ServerConnectionManager forcing SYNC_AUTH_ERROR
[76384:107271:1215/113624.552843:WARNING:syncer_proto_util.cc(338)] Error posting from syncer: Response Code (bogus on error): -1 Content-Length (bogus on error): -1 Server Status: SYNC_AUTH_ERROR
[76384:107271:1215/113624.555024:WARNING:sync_encryption_handler_impl.cc(971)] Nigori had empty encryption keybag.
[76384:107271:1215/113624.555348:WARNING:sync_encryption_handler_impl.cc(971)] Nigori had empty encryption keybag.
[76384:107271:1215/113624.570185:WARNING:sync_encryption_handler_impl.cc(347)] Ignoring new implicit passphrase. Keystore migration already performed.
[76384:110339:1215/113624.608909:WARNING:server_connection_manager.cc(269)] ServerConnectionManager forcing SYNC_AUTH_ERROR
[76384:110339:1215/113624.608949:WARNING:syncer_proto_util.cc(338)] Error posting from syncer: Response Code (bogus on error): -1 Content-Length (bogus on error): -1 Server Status: SYNC_AUTH_ERROR
[76384:110339:1215/113624.623304:WARNING:sync_encryption_handler_impl.cc(347)] Ignoring new implicit passphrase. Keystore migration already performed.
[76384:47379:1215/113643.758981:ERROR:binary_integrity_analyzer_mac.cc(31)] Could not initialize mac signature evaluator
BrowserTestBase received signal: Terminated: 15. Backtrace:
0   sync_integration_tests              0x00000001085eccc3 _ZN4base5debug10StackTraceC1Ev + 19
1   sync_integration_tests              0x000000010c83fdaa _ZN7content12_GLOBAL__N_1L27DumpStackTraceSignalHandlerEi + 202
2   libsystem_platform.dylib            0x00007fff9eed6bba _sigtramp + 26
3   libsystem_pthread.dylib             0x00007fff9eedf662 _pthread_cond_signal + 645
4   CoreFoundation                      0x00007fff89a62834 __CFRunLoopServiceMachPort + 212
5   CoreFoundation                      0x00007fff89a61cc1 __CFRunLoopRun + 1361
6   CoreFoundation                      0x00007fff89a61514 CFRunLoopRunSpecific + 420
7   HIToolbox                           0x00007fff88ff22ac RunCurrentEventLoopInMode + 240
8   HIToolbox                           0x00007fff88ff20e1 ReceiveNextEventCommon + 432
9   HIToolbox                           0x00007fff88ff1f16 _BlockUntilNextEventMatchingListInModeWithFilter + 71
10  AppKit                              0x00007fff875f46cd _DPSNextEvent + 1093
11  AppKit                              0x00007fff87d6b830 -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 2730
12  sync_integration_tests              0x0000000108904e50 __71-[BrowserCrApplication nextEventMatchingMask:untilDate:inMode:dequeue:]_block_invoke + 64
13  sync_integration_tests              0x000000010860700a _ZN4base3mac15CallWithEHFrameEU13block_pointerFvvE + 10
14  sync_integration_tests              0x0000000108904d89 -[BrowserCrApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 169
15  AppKit                              0x00007fff875e906d -[NSApplication run] + 926
16  sync_integration_tests              0x000000010861623e _ZN4base24MessagePumpNSApplication5DoRunEPNS_11MessagePump8DelegateE + 334
17  sync_integration_tests              0x000000010861588c _ZN4base24MessagePumpCFRunLoopBase3RunEPNS_11MessagePump8DelegateE + 92
18  sync_integration_tests              0x000000010861297e _ZN4base11MessageLoop10RunHandlerEv + 94
19  sync_integration_tests              0x0000000108634e93 _ZN4base7RunLoop3RunEv + 115
20  sync_integration_tests              0x0000000108386a82 _ZN19StatusChangeChecker17StartBlockingWaitEv + 258
21  sync_integration_tests              0x000000010838696b _ZN19StatusChangeChecker4WaitEv + 27
22  sync_integration_tests              0x0000000106ec66cb _ZN12_GLOBAL__N_139TwoClientUssSyncTest_DisableEnable_Test19RunTestOnMainThreadEv + 3323
23  sync_integration_tests              0x0000000108399921 _ZN20InProcessBrowserTest23RunTestOnMainThreadLoopEv + 209
24  sync_integration_tests              0x000000010c83fb16 _ZN7content15BrowserTestBase28ProxyRunTestOnMainThreadLoopEv + 278
25  sync_integration_tests              0x0000000108909cda _ZN22ChromeBrowserMainParts25PreMainMessageLoopRunImplEv + 4250
26  sync_integration_tests              0x0000000108908b3e _ZN22ChromeBrowserMainParts21PreMainMessageLoopRunEv + 62
27  sync_integration_tests              0x0000000107beb263 _ZN7content15BrowserMainLoop21PreMainMessageLoopRunEv + 67
28  sync_integration_tests              0x0000000107f001b6 _ZN7content17StartupTaskRunner14RunAllTasksNowEv + 38
29  sync_integration_tests              0x0000000107be9552 _ZN7content15BrowserMainLoop18CreateStartupTasksEv + 658
30  sync_integration_tests              0x0000000107bedf4b _ZN7content21BrowserMainRunnerImpl10InitializeERKNS_18MainFunctionParamsE + 683
31  sync_integration_tests              0x0000000107be6f34 _ZN7content11BrowserMainERKNS_18MainFunctionParamsE + 100
32  sync_integration_tests              0x000000010835a5a0 _ZN7content21ContentMainRunnerImpl3RunEv + 368
33  sync_integration_tests              0x00000001083597a6 _ZN7content11ContentMainERKNS_17ContentMainParamsE + 54
34  sync_integration_tests              0x000000010c83f822 _ZN7content15BrowserTestBase5SetUpEv + 1906
35  sync_integration_tests              0x0000000108398de5 _ZN20InProcessBrowserTest5SetUpEv + 389
36  sync_integration_tests              0x000000010838c34b _ZN8SyncTest5SetUpEv + 635
37  sync_integration_tests              0x0000000108516deb _ZN7testing4Test3RunEv + 299
38  sync_integration_tests              0x00000001085179e0 _ZN7testing8TestInfo3RunEv + 576
39  sync_integration_tests              0x0000000108518097 _ZN7testing8TestCase3RunEv + 455
40  sync_integration_tests              0x000000010851e007 _ZN7testing8internal12UnitTestImpl11RunAllTestsEv + 967
41  sync_integration_tests              0x000000010851dc09 _ZN7testing8UnitTest3RunEv + 265
42  sync_integration_tests              0x00000001085d9c75 _ZN4base9TestSuite3RunEv + 133
43  sync_integration_tests              0x000000010839723f _ZN21ChromeTestSuiteRunner12RunTestSuiteEiPPc + 31
44  sync_integration_tests              0x000000010c8411fe _ZN7content11LaunchTestsEPNS_20TestLauncherDelegateEiiPPc + 302
45  sync_integration_tests              0x00000001083691da main + 90
46  libdyld.dylib                       0x00007fff9ecc9255 start + 1
"""

The test fails with the same error when I ssh into the machine and run it [time out]. When I run the test on a local 10.11 machine, I don't get an error. Logging shows that there are additional lines not being printed during the failure.
"""
ChildAccountInfoFetcherImpl::OnGetUserInfoSuccess:
"""

"""
[83111:775:1215/122526.476902:WARNING:vt_video_decode_accelerator_mac.cc(169)] Failed to create VTDecompressionSession: Error Domain=NSOSStatusErrorDomain Code=-8973 "codecOpenErr" (-8973)
[83111:775:1215/122526.477372:WARNING:vt_video_decode_accelerator_mac.cc(191)] Failed to create hardware VideoToolbox session
[83111:775:1215/122526.584072:ERROR:vt_video_encode_accelerator_mac.cc(518)]  VTCompressionSessionCreate failed: -12908
[83108:775:1215/122527.194816:ERROR:child_account_info_fetcher_impl.cc(144)] ChildAccountInfoFetcherImpl::OnGetUserInfoSuccess: GetUserInfo response didn't include allServices field.
[83108:119323:1215/122527.204451:WARNING:server_connection_manager.cc(269)] ServerConnectionManager forcing SYNC_AUTH_ERROR
[83108:119323:1215/122527.204595:WARNING:syncer_proto_util.cc(338)] Error posting from syncer: Response Code (bogus on error): -1 Content-Length (bogus on error): -1 Server Status: SYNC_AUTH_ERROR
[83108:119323:1215/122527.206895:WARNING:sync_encryption_handler_impl.cc(971)] Nigori had empty encryption keybag.
[83108:119323:1215/122527.207971:WARNING:sync_encryption_handler_impl.cc(971)] Nigori had empty encryption keybag.
[83108:119323:1215/122527.224545:WARNING:sync_encryption_handler_impl.cc(347)] Ignoring new implicit passphrase. Keystore migration already performed.
[83108:775:1215/122527.255017:ERROR:child_account_info_fetcher_impl.cc(144)] ChildAccountInfoFetcherImpl::OnGetUserInfoSuccess: GetUserInfo response didn't include allServices field.
[83108:122627:1215/122527.262126:WARNING:server_connection_manager.cc(269)] ServerConnectionManager forcing SYNC_AUTH_ERROR
[83108:122627:1215/122527.262274:WARNING:syncer_proto_util.cc(338)] Error posting from syncer: Response Code (bogus on error): -1 Content-Length (bogus on error): -1 Server Status: SYNC_AUTH_ERROR
[83108:122627:1215/122527.279639:WARNING:sync_encryption_handler_impl.cc(347)] Ignoring new implicit passphrase. Keystore migration already performed.
"""