This issue is first seen on M67-67.0.3396.99. But, recently spiked in latest Stable M69- 69.0.3497.100. Below link gives in detail of the number of instances in which the crash occurred for associated builds:

https://crash.corp.google.com/browse?q=product_name%3D%27Chrome_Mac%27+AND+expanded_custom_data.ChromeCrashProto.ptype%3D%27browser%27+AND+expanded_custom_data.ChromeCrashProto.magic_signature_1.name%3D%27%5BUncaught+NSException%5D+NSInternalInconsistencyException+reason+-%5BNSCGSFence+set%5D+called+after+-%5BNSCGSFence+invalidate%5D%27#-productname:1000,productversion:100,-magicsignature:50,-magicsignature2:50,-stablesignature:50,-magicsignaturesorted:50

Note:
=====
1. This is Browser crash listed under Beta build 70.0.3538.35 for Mac on 3 different client ID's.
2. Currently this crash is ranked as number #16 with 3 instances
3. This crash is observed only on Mac platform.
4. Since there are low instances of crashes, not marking this crash as RB. Please feel free to edit if this is not the case.
5. All the crashes are observed in '10.14 (Mojave)'. Hence, adding the label 'Proj-MacMojave'.

Crash data:
-----------
70.0.3538.35	2.31%	3 - Beta
69.0.3497.100	66.15%	86 - Stable

As we are unable to pinpoint the exact suspect, requesting Stability Sheriff to look into this issue.

Thanks!

firstexception_bt is not illuminating:

0x0233238c [Google Chrome Framework -	 safe_conversions.h:180] base::debug::StackTrace::StackTrace(unsigned long)
0x01f5543d [Google Chrome Framework -	 exception_processor.mm:124] chrome::ObjcExceptionPreprocessor(objc_object*)
0x00015efb [libobjc.A.dylib +	 0x15efb] objc_exception_throw
0x000f53a3 [CoreFoundation +	 0xf53a3] +[NSException raise:format:]
0x0030ae43 [AppKit +	 0x30ae43] __42-[NSAnimation(NSInternal) _runInNewThread]_block_invoke_2
0x00054172 [AppKit +	 0x54172] NSPerformVisuallyAtomicChange
0x0030ae02 [AppKit +	 0x30ae02] __42-[NSAnimation(NSInternal) _runInNewThread]_block_invoke
0x00002d4f [libdispatch.dylib +	 0x2d4f] _dispatch_call_block_and_release
0x00003dcb [libdispatch.dylib +	 0x3dcb] _dispatch_client_callout
0x00011e74 [libdispatch.dylib +	 0x11e74] _dispatch_root_queue_drain
0x000124b1 [libdispatch.dylib +	 0x124b1] _dispatch_worker_thread2
0x000026ee [libsystem_pthread.dylib +	 0x26ee] _pthread_wqthread
0x00002415 [libsystem_pthread.dylib +	 0x2415] start_wqthread

Assuming this is from an NSAnimation we actually created, potential culprits are:

ViewsNSWindowCloseAnimator
ConstrainedWindowAnimationBase
MCPopupController
ConfirmQuitPanelController
ConstrainedWindowCustomSheet

I *believe* that the latter three are all Cocoa-specific and this crash only shows up on MacViews, so I'd be inclined to look hard at ViewsNSWindowCloseAnimator and ConstrainedWindowAnimationBase. To add to this suspicion, ViewsNSWindowCloseAnimator uses NSAnimationNonBlocking for its blocking mode, which I could believe is triggering a bug within AppKit.

Notably, 100% of crashes are from 10.14.

Stripping R-V-EI and let's target a fix at M71.

Thanks for triaging, removing from stability sheriff queue.

I think you're right re: ViewsNSWindowCloseAnimation. The main thread is doing something interesting:

Stack Quality84%Show frame trust levels
0x00007fff7a05fc2a	(libsystem_kernel.dylib + 0x00000c2a )	mach_msg_trap
0x000000010b38ce5c	(Google Chrome Framework -waitable_event_mac.cc:142 )	base::WaitableEvent::TimedWaitUntil(base::TimeTicks const&)
0x000000010b38cd5e	(Google Chrome Framework -waitable_event_mac.cc:105 )	base::WaitableEvent::Wait()
0x0000000109838478	(Google Chrome Framework -gpu_channel_host.cc:83 )	gpu::GpuChannelHost::Send(IPC::Message*)
0x0000000109835427	(Google Chrome Framework -command_buffer_proxy_impl.cc:681 )	gpu::CommandBufferProxyImpl::WaitForGetOffsetInRange(unsigned int, int, int)
0x0000000109779ece	(Google Chrome Framework -cmd_buffer_helper.cc:166 )	gpu::CommandBufferHelper::Finish()
0x000000010c186f56	(Google Chrome Framework -implementation_base.cc:176 )	gpu::ImplementationBase::WaitForCmd()
0x000000010c15214b	(Google Chrome Framework -gles2_implementation.cc:305 )	gpu::gles2::GLES2Implementation::~GLES2Implementation()
0x000000010984694d	(Google Chrome Framework -gles2_implementation_with_grcontext_support.cc:33 )	<name omitted>
0x000000010a18b431	(Google Chrome Framework -memory:2321 )	ui::ContextProviderCommandBuffer::~ContextProviderCommandBuffer()
0x000000010a18b52d	(Google Chrome Framework -context_provider_command_buffer.cc:76 )	<name omitted>
0x0000000109ffab7d	(Google Chrome Framework -gpu_output_surface_mac.cc:32 )	content::GpuOutputSurfaceMac::~GpuOutputSurfaceMac()
0x000000010c6d04bf	(Google Chrome Framework -memory:2321 )	viz::Display::~Display()
0x000000010c6d057d	(Google Chrome Framework -display.cc:63 )	<name omitted>
0x0000000109ffe186	(Google Chrome Framework -memory:2321 )	std::__1::__tree<std::__1::__value_type<ui::Compositor*, std::__1::unique_ptr<content::GpuProcessTransportFactory::PerCompositorData, std::__1::default_delete<content::GpuProcessTransportFactory::PerCompositorData> > >, std::__1::__map_value_compare<ui::Compositor*, std::__1::__value_type<ui::Compositor*, std::__1::unique_ptr<content::GpuProcessTransportFactory::PerCompositorData, std::__1::default_delete<content::GpuProcessTransportFactory::PerCompositorData> > >, std::__1::less<ui::Compositor*>, true>, std::__1::allocator<std::__1::__value_type<ui::Compositor*, std::__1::unique_ptr<content::GpuProcessTransportFactory::PerCompositorData, std::__1::default_delete<content::GpuProcessTransportFactory::PerCompositorData> > > > >::erase(std::__1::__tree_const_iterator<std::__1::__value_type<ui::Compositor*, std::__1::unique_ptr<content::GpuProcessTransportFactory::PerCompositorData, std::__1::default_delete<content::GpuProcessTransportFactory::PerCompositorData> > >, std::__1::__tree_node<std::__1::__value_type<ui::Compositor*, std::__1::unique_ptr<content::GpuProcessTransportFactory::PerCompositorData, std::__1::default_delete<content::GpuProcessTransportFactory::PerCompositorData> > >, void*>*, long>)
0x0000000109ffce6e	(Google Chrome Framework -map:1246 )	content::GpuProcessTransportFactory::RemoveCompositor(ui::Compositor*)
0x000000010cbf0575	(Google Chrome Framework -compositor.cc:245 )	ui::Compositor::~Compositor()
0x000000010cc02a0b	(Google Chrome Framework -recyclable_compositor_mac.cc:59 )	ui::RecyclableCompositorMac::~RecyclableCompositorMac()
0x000000010cc02d5a	(Google Chrome Framework -memory:2321 )	ui::RecyclableCompositorMacFactory::RecycleCompositor(std::__1::unique_ptr<ui::RecyclableCompositorMac, std::__1::default_delete<ui::RecyclableCompositorMac> >)
0x000000010cb6c19d	(Google Chrome Framework -bridged_native_widget.mm:1293 )	views::BridgedNativeWidget::DestroyCompositor()
0x000000010cb6bbda	(Google Chrome Framework -bridged_native_widget.mm:260 )	views::BridgedNativeWidget::~BridgedNativeWidget()
0x000000010cb6c25d	(Google Chrome Framework -bridged_native_widget.mm:249 )	<name omitted>
0x000000010cbd9e4f	(Google Chrome Framework -memory:2321 )	views::NativeWidgetMac::WindowDestroyed()
0x000000010cb71844	(Google Chrome Framework -views_nswindow_delegate.mm:146 )	-[ViewsNSWindowDelegate windowWillClose:]
0x00007fff4ce5a075	(CoreFoundation + 0x000a0075 )	__CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__
0x00007fff4ce59fef	(CoreFoundation + 0x0009ffef )	___CFXRegistrationPost_block_invoke
0x00007fff4ce59f10	(CoreFoundation + 0x0009ff10 )	_CFXRegistrationPost
0x00007fff4ce6224c	(CoreFoundation + 0x000a824c )	___CFXNotificationPost_block_invoke
0x00007fff4cdc93a3	(CoreFoundation + 0x0000f3a3 )	-[_CFXNotificationRegistrar find:object:observer:enumerator:]
0x00007fff4cdc8648	(CoreFoundation + 0x0000e648 )	_CFXNotificationPost
0x00007fff4f168baa	(Foundation + 0x00011baa )	-[NSNotificationCenter postNotificationName:object:userInfo:]
0x00007fff4ac54884	(AppKit + 0x00931884 )	-[NSWindow _finishClosingWindow]
0x00007fff4a6c3c63	(AppKit + 0x003a0c63 )	-[NSWindow _close]
0x000000010cb71b01	(Google Chrome Framework -bind_internal.h:489 )	base::internal::Invoker<base::internal::BindState<base::mac::ScopedBlock<void () block_pointer> >, void ()>::RunOnce(base::internal::BindStateBase*)
0x000000010b332131	(Google Chrome Framework -callback.h:99 )	base::debug::TaskAnnotator::RunTask(char const*, base::PendingTask*)
0x000000010b35161e	(Google Chrome Framework -message_loop.cc:421 )	base::MessageLoop::RunTask(base::PendingTask*)
0x000000010b351ae7	(Google Chrome Framework -message_loop.cc:432 )	base::MessageLoop::DoWork()
0x000000010b353ca9	(Google Chrome Framework -message_pump_mac.mm:455 )	base::MessagePumpCFRunLoopBase::RunWork()
0x000000010b3441e9	(Google Chrome Framework + 0x022971e9 )	base::mac::CallWithEHFrame(void () block_pointer)
0x000000010b3535ce	(Google Chrome Framework -message_pump_mac.mm:431 )	base::MessagePumpCFRunLoopBase::RunWorkSource(void*)
0x00007fff4ce12128	(CoreFoundation + 0x00058128 )	__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__
0x00007fff4ce120ce	(CoreFoundation + 0x000580ce )	__CFRunLoopDoSource0
0x00007fff4cdf5f6f	(CoreFoundation + 0x0003bf6f )	__CFRunLoopDoSources0
0x00007fff4cdf5516	(CoreFoundation + 0x0003b516 )	__CFRunLoopRun
0x00007fff4cdf4df9	(CoreFoundation + 0x0003adf9 )	CFRunLoopRunSpecific
0x00007fff4c080894	(HIToolbox + 0x0000a894 )	RunCurrentEventLoopInMode
0x00007fff4c0805ca	(HIToolbox + 0x0000a5ca )	ReceiveNextEventCommon
0x00007fff4c080347	(HIToolbox + 0x0000a347 )	_BlockUntilNextEventMatchingListInModeWithFilter
0x00007fff4a33d95a	(AppKit + 0x0001a95a )	_DPSNextEvent
0x00007fff4a33c6f9	(AppKit + 0x000196f9 )	-[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:]
0x000000010af6895f	(Google Chrome Framework -chrome_browser_application_mac.mm:233 )	__71-[BrowserCrApplication nextEventMatchingMask:untilDate:inMode:dequeue:]_block_invoke
0x000000010b3441e9	(Google Chrome Framework + 0x022971e9 )	base::mac::CallWithEHFrame(void () block_pointer)
0x000000010af68893	(Google Chrome Framework -chrome_browser_application_mac.mm:232 )	-[BrowserCrApplication nextEventMatchingMask:untilDate:inMode:dequeue:]
0x00007fff4a33675c	(AppKit + 0x0001375c )	-[NSApplication run]
0x000000010b35456b	(Google Chrome Framework -message_pump_mac.mm:808 )	base::MessagePumpNSApplication::DoRun(base::MessagePump::Delegate*)
0x000000010b3530ed	(Google Chrome Framework -message_pump_mac.mm:184 )	base::MessagePumpCFRunLoopBase::Run(base::MessagePump::Delegate*)
0x000000010b375c24	(Google Chrome Framework -run_loop.cc:102 )	<name omitted>
0x000000010af6f40a	(Google Chrome Framework -chrome_browser_main.cc:2086 )	ChromeBrowserMainParts::MainMessageLoopRun(int*)
0x0000000109b551b3	(Google Chrome Framework -browser_main_loop.cc:1034 )	content::BrowserMainLoop::RunMainMessageLoopParts()
0x0000000109b57901	(Google Chrome Framework -browser_main_runner_impl.cc:162 )	content::BrowserMainRunnerImpl::Run()
0x0000000109b51c6a	(Google Chrome Framework -browser_main.cc:47 )	content::BrowserMain(content::MainFunctionParams const&)
0x000000010af23097	(Google Chrome Framework -content_main_runner_impl.cc:596 )	content::ContentMainRunnerImpl::Run(bool)
0x000000010c7d312c	(Google Chrome Framework -main.cc:472 )	service_manager::Main(service_manager::MainParams const&)
0x000000010af22143	(Google Chrome Framework -content_main.cc:19 )	content::ContentMain(content::ContentMainParams const&)
0x00000001090b11f2	(Google Chrome Framework -chrome_main.cc:101 )	ChromeMain
0x0000000101bacdd0	(Google Chrome -chrome_exe_main_mac.cc:101 )	main
0x00007fff79f27084	(libdyld.dylib + 0x00017084 )	start