Stack backtrace:

(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BREAKPOINT (code=EXC_I386_BPT, subcode=0x0)
    frame #0: 0x0000000109554004 ios_chrome_perftests`base::debug::BreakDebugger() at debugger_posix.cc:262
    frame #1: 0x00000001095c7d48 ios_chrome_perftests`logging::LogMessage::~LogMessage(this=0x00007fff57a8a820) at logging.cc:783
    frame #2: 0x00000001095c4865 ios_chrome_perftests`logging::LogMessage::~LogMessage(this=0x00007fff57a8a820) at logging.cc:546
  * frame #3: 0x0000000109026f5d ios_chrome_perftests`PerfTestWithBVC::SetUp(this=0x00007fc5d9404b00) at perf_test_with_bvc_ios.mm:124
    frame #4: 0x0000000108179fcf ios_chrome_perftests`(anonymous namespace)::NewTabPagePerfTest::SetUp(this=0x00007fc5d9404b00) at new_tab_page_perftest.mm:33
    frame #5: 0x0000000109bff85e ios_chrome_perftests`void testing::internal::HandleSehExceptionsInMethodIfSupported<testing::Test, void>(object=0x00007fc5d9404b00, method=11 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00, location="SetUp()")(), char const*) at gtest.cc:2402
    frame #6: 0x0000000109bdd522 ios_chrome_perftests`void testing::internal::HandleExceptionsInMethodIfSupported<testing::Test, void>(object=0x00007fc5d9404b00, method=11 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00, location="SetUp()")(), char const*) at gtest.cc:2455
    frame #7: 0x0000000109bdd404 ios_chrome_perftests`testing::Test::Run(this=0x00007fc5d9404b00) at gtest.cc:2470
    frame #8: 0x0000000109bde5cd ios_chrome_perftests`testing::TestInfo::Run(this=0x00007fc5dc600a70) at gtest.cc:2656
    frame #9: 0x0000000109bdf86c ios_chrome_perftests`testing::TestCase::Run(this=0x00007fc5dc600b80) at gtest.cc:2774
    frame #10: 0x0000000109beca19 ios_chrome_perftests`testing::internal::UnitTestImpl::RunAllTests(this=0x00007fc5dc600640) at gtest.cc:4647
    frame #11: 0x0000000109c02a4e ios_chrome_perftests`bool testing::internal::HandleSehExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(object=0x00007fc5dc600640, method=b0 c6 be 09 01 00 00 00 00 00 00 00 00 00 00 00, location="auxiliary test code (environments or event listeners)")(), char const*) at gtest.cc:2402
    frame #12: 0x0000000109bec632 ios_chrome_perftests`bool testing::internal::HandleExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(object=0x00007fc5dc600640, method=b0 c6 be 09 01 00 00 00 00 00 00 00 00 00 00 00, location="auxiliary test code (environments or event listeners)")(), char const*) at gtest.cc:2455
    frame #13: 0x0000000109bec52a ios_chrome_perftests`testing::UnitTest::Run(this=0x000000010dc106a8) at gtest.cc:4255
    frame #14: 0x00000001098e0321 ios_chrome_perftests`RUN_ALL_TESTS() at gtest.h:2237
    frame #15: 0x00000001098df6eb ios_chrome_perftests`base::TestSuite::Run(this=0x00007fff57a8d698) at test_suite.cc:271
    frame #16: 0x00000001098e39bc ios_chrome_perftests`::-[ChromeUnitTestDelegate runTests](self=0x0000620000012f20, _cmd="runTests") at test_support_ios.mm:155
    frame #17: 0x00000001156831a8 Foundation`__NSFireDelayedPerform + 409
    frame #18: 0x00000001148b0454 CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 20
    frame #19: 0x00000001148b00e3 CoreFoundation`__CFRunLoopDoTimer + 1011
    frame #20: 0x00000001148afcaa CoreFoundation`__CFRunLoopDoTimers + 266
    frame #21: 0x00000001148a79ec CoreFoundation`__CFRunLoopRun + 1916
    frame #22: 0x00000001148a7016 CoreFoundation`CFRunLoopRunSpecific + 406
    frame #23: 0x000000011a05aa24 GraphicsServices`GSEventRunModal + 62
    frame #24: 0x0000000112fcc0d4 UIKit`UIApplicationMain + 159
    frame #25: 0x00000001098e3c62 ios_chrome_perftests`base::RunTestsFromIOSApp() at test_support_ios.mm:213
    frame #26: 0x00000001098df5cf ios_chrome_perftests`base::TestSuite::Run(this=0x00007fff57a8d698) at test_suite.cc:252
    frame #27: 0x0000000108172f25 ios_chrome_perftests`int base::internal::FunctorTraits<int (base::TestSuite::*)(), void>::Invoke<IOSChromeUnitTestSuite*>(method=b0 f5 8d 09 01 00 00 00 00 00 00 00 00 00 00 00, receiver_ptr=0x00007fff57a8d210)(), IOSChromeUnitTestSuite*&&) at bind_internal.h:214
    frame #28: 0x0000000108172e64 ios_chrome_perftests`int base::internal::InvokeHelper<false, int>::MakeItSo<int (functor=0x000065000006e4e8, args=0x00007fff57a8d210)(), IOSChromeUnitTestSuite*>(int (base::TestSuite::* const&&&)(), IOSChromeUnitTestSuite*&&) at bind_internal.h:285
    frame #29: 0x0000000108172e15 ios_chrome_perftests`int base::internal::Invoker<base::internal::BindState<int (base::TestSuite::*)(), base::internal::UnretainedWrapper<IOSChromeUnitTestSuite> >, int ()>::RunImpl<int (functor=0x000065000006e4e8, bound=0x000065000006e4f8, (null)=IndexSequence<0> @ 0x00007fff57a8d228)(), std::__1::tuple<base::internal::UnretainedWrapper<IOSChromeUnitTestSuite> > const&, 0ul>(int (base::TestSuite::* const&&&)(), std::__1::tuple<base::internal::UnretainedWrapper<IOSChromeUnitTestSuite> > const&&&, base::IndexSequence<0ul>) at bind_internal.h:361
    frame #30: 0x0000000108172d2c ios_chrome_perftests`base::internal::Invoker<base::internal::BindState<int (base::TestSuite::*)(), base::internal::UnretainedWrapper<IOSChromeUnitTestSuite> >, int ()>::Run(base=0x000065000006e4c0) at bind_internal.h:339
    frame #31: 0x00000001098e5b9d ios_chrome_perftests`base::Callback<int (), (base::internal::CopyMode)1, (base::internal::RepeatMode)1>::Run(this=0x00007fff57a8d680) const at callback.h:80
    frame #32: 0x00000001098e5b1c ios_chrome_perftests`base::LaunchUnitTests(argc=1, argv=0x00007fff57a8d720, run_test_suite=0x00007fff57a8d680), (base::internal::CopyMode)1, (base::internal::RepeatMode)1> const&) at unit_test_launcher_ios.cc:39
    frame #33: 0x0000000108172a92 ios_chrome_perftests`main(argc=1, argv=0x00007fff57a8d720) at run_all_unittests.cc:12
    frame #34: 0x000000011c7ab65d libdyld.dylib`start + 1
(lldb) 

In PerfTestWithBVC::SetUp(), DCHECK_EQ(session.sessionWindows.count, 1u) failed.