Chrome Version: 7f95c8453a369c61e3c2bf23a7fb7c8ea60b1e6b
macOS 10.12.6

What steps will reproduce the problem?
(1) In args.gn: `dcheck_always_on = true`
(1) ninja -C out/Release chrome
(2) ./out/Release/Chromium.app/Contents/MacOS/Chromium "badssl.com"

What is the expected result?
Happy loading.

What happens instead?
A significant fraction of the time, I get an "Aw, Snap!" page.

    [55860:26115:1025/173916.975425:FATAL:proxy_impl.cc(527)] Check failed: host_impl_->CanDraw().
    0   libbase.dylib                       0x0000000111c4884c base::debug::StackTrace::StackTrace(unsigned long) + 28
    1   libbase.dylib                       0x0000000111c73192 logging::LogMessage::~LogMessage() + 210
    2   libcc.dylib                         0x0000000113e2cc53 cc::ProxyImpl::ScheduledActionDrawIfPossible() + 211
    3   libcc.dylib                         0x0000000113d8188e cc::Scheduler::ProcessScheduledActions() + 846
    4   libcc.dylib                         0x0000000113d813b2 cc::Scheduler::OnBeginImplFrameDeadline() + 210
    5   libcc.dylib                         0x0000000113d850b7 base::internal::Invoker<base::internal::BindState<void (cc::Scheduler::*)(), base::WeakPtr<cc::Scheduler> >, void ()>::Run(base::internal::BindStateBase*) + 183
    6   libcc.dylib                         0x0000000113d13ec1 base::CancelableCallback<void ()>::Forward() const + 97
    7   libcc.dylib                         0x0000000113d14027 base::internal::Invoker<base::internal::BindState<void (base::CancelableCallback<void ()>::*)() const, base::WeakPtr<base::CancelableCallback<void ()> > >, void ()>::Run(base::internal::BindStateBase*) + 183
    8   libbase.dylib                       0x0000000111c491d5 base::debug::TaskAnnotator::RunTask(char const*, base::PendingTask*) + 261
    9   libblink_platform.dylib             0x000000011f367bee blink::scheduler::TaskQueueManager::ProcessTaskFromWorkQueue(blink::scheduler::internal::WorkQueue*, bool, blink::scheduler::LazyNow, base::TimeTicks*) + 1390
    10  libblink_platform.dylib             0x000000011f3653fd blink::scheduler::TaskQueueManager::DoWork(bool) + 1149
    11  libblink_platform.dylib             0x000000011f36a03e void base::internal::InvokeHelper<true, void>::MakeItSo<void (blink::scheduler::TaskQueueManager::* const&)(bool), base::WeakPtr<blink::scheduler::TaskQueueManager> const&, bool const&>(void (blink::scheduler::TaskQueueManager::* const&&&)(bool), base::WeakPtr<blink::scheduler::TaskQueueManager> const&&&, bool const&&&) + 190
    12  libbase.dylib                       0x0000000111c491d5 base::debug::TaskAnnotator::RunTask(char const*, base::PendingTask*) + 261
    13  libbase.dylib                       0x0000000111c8a069 base::internal::IncomingTaskQueue::RunTask(base::PendingTask*) + 121
    14  libbase.dylib                       0x0000000111c8e777 base::MessageLoop::RunTask(base::PendingTask*) + 519
    15  libbase.dylib                       0x0000000111c8ebba base::MessageLoop::DeferOrRunPendingTask(base::PendingTask) + 202
    16  libbase.dylib                       0x0000000111c8ee51 base::MessageLoop::DoWork() + 609
    17  libbase.dylib                       0x0000000111c92caa base::MessagePumpCFRunLoopBase::RunWork() + 42
    18  libbase.dylib                       0x0000000111c750fa base::mac::CallWithEHFrame(void () block_pointer) + 10
    19  libbase.dylib                       0x0000000111c9258f base::MessagePumpCFRunLoopBase::RunWorkSource(void*) + 63
    20  CoreFoundation                      0x00007fffc87143e1 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
    21  CoreFoundation                      0x00007fffc86f565c __CFRunLoopDoSources0 + 556
    22  CoreFoundation                      0x00007fffc86f4b46 __CFRunLoopRun + 934
    23  CoreFoundation                      0x00007fffc86f4544 CFRunLoopRunSpecific + 420
    24  libbase.dylib                       0x0000000111c9314f base::MessagePumpCFRunLoop::DoRun(base::MessagePump::Delegate*) + 79
    25  libbase.dylib                       0x0000000111c91fde base::MessagePumpCFRunLoopBase::Run(base::MessagePump::Delegate*) + 110
    26  libbase.dylib                       0x0000000111c8e142 base::MessageLoop::Run() + 146
    27  libbase.dylib                       0x0000000111ccc4ff base::RunLoop::Run() + 127
    28  libbase.dylib                       0x0000000111d19fae base::Thread::Run(base::RunLoop*) + 206
    29  libbase.dylib                       0x0000000111d1a56c base::Thread::ThreadMain() + 908
    30  libbase.dylib                       0x0000000111d0f45f base::(anonymous namespace)::ThreadFunc(void*) + 95
    31  libsystem_pthread.dylib             0x00007fffde4d893b _pthread_body + 180
    32  libsystem_pthread.dylib             0x00007fffde4d8887 _pthread_body + 0
    33  libsystem_pthread.dylib             0x00007fffde4d808d thread_start + 13

Here are the contents of my out/Release/args.gn file, in case it helps:

    # Debug/Release
    is_debug = false

    # Faster Builds
    enable_nacl = false
    is_component_build = true
    symbol_level = 1
    use_goma = true

    # Catchin' Bugs
    # https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/0fit7KBlaUY
    dcheck_always_on = true

    # DevTools
    debug_devtools = true

danakj@, could you triage?