Chrome Remote Desktop version: 67.0.3376.0

What steps will reproduce the problem?
(1) Share your desktop using IT2Me and the webrtc client.
(2) In another window, enter the access code.
(3) When prompted to confirm, click Cancel.

What is the expected result?
The connection is canceled  and the helper is notified with a suitable error.

What happens instead?
A DCHECK fires in validating_authenticator.cc:

[0319/131958.638501:FATAL:validating_authenticator.cc(74)] Check failed: state_ == ACCEPTED || state_ == WAITING_MESSAGE. 
#0 0x00000284120d base::debug::StackTrace::StackTrace()
#1 0x00000283f92c base::debug::StackTrace::StackTrace()
#2 0x0000028a4a4a logging::LogMessage::~LogMessage()
#3 0x000003968a75 remoting::protocol::ValidatingAuthenticator::GetNextMessage()
#4 0x000003920b42 remoting::protocol::JingleSession::ProcessAuthenticationStep()
#5 0x000000da3a5d _ZN4base8internal13FunctorTraitsIMN8remoting21NativeMessagingReader4CoreEFvvEvE6InvokeIPS4_JEEEvS6_OT_DpOT0_
#6 0x000000da39d4 _ZN4base8internal12InvokeHelperILb0EvE8MakeItSoIRKMN8remoting21NativeMessagingReader4CoreEFvvEJPS6_EEEvOT_DpOT0_
#7 0x000000da3985 _ZN4base8internal7InvokerINS0_9BindStateIMN8remoting21NativeMessagingReader4CoreEFvvEJNS0_17UnretainedWrapperIS5_EEEEEFvvEE7RunImplIRKS7_RKNSt3__15tupleIJS9_EEEJLm0EEEEvOT_OT0_NSG_16integer_sequenceImJXspT1_EEEE
#8 0x000000da391c _ZN4base8internal7InvokerINS0_9BindStateIMN8remoting21NativeMessagingReader4CoreEFvvEJNS0_17UnretainedWrapperIS5_EEEEEFvvEE3RunEPNS0_13BindStateBaseE
#9 0x000000d9aa6d _ZNKR4base17RepeatingCallbackIFvvEE3RunEv
#10 0x000003969061 remoting::protocol::ValidatingAuthenticator::OnValidateComplete()
#11 0x000001dfb741 _ZN4base8internal13FunctorTraitsIMN5media13FFmpegDemuxerEFvRKNS_17RepeatingCallbackIFvNS2_14PipelineStatusEEEEiEvE6InvokeIRKNS_7WeakPtrIS3_EEJS9_iEEEvSB_OT_DpOT0_
#12 0x000001dfb695 _ZN4base8internal12InvokeHelperILb1EvE8MakeItSoIRKMN5media13FFmpegDemuxerEFvRKNS_17RepeatingCallbackIFvNS4_14PipelineStatusEEEEiERKNS_7WeakPtrIS5_EEJSB_iEEEvOT_OT0_DpOT1_
#13 0x000001dfb5fd _ZN4base8internal7InvokerINS0_9BindStateIMN5media13FFmpegDemuxerEFvRKNS_17RepeatingCallbackIFvNS3_14PipelineStatusEEEEiEJNS_7WeakPtrIS4_EES8_EEEFviEE7RunImplIRKSC_RKNSt3__15tupleIJSE_S8_EEEJLm0ELm1EEEEvOT_OT0_NSL_16integer_sequenceImJXspT1_EEEEOi
#14 0x000001dfb55b _ZN4base8internal7InvokerINS0_9BindStateIMN5media13FFmpegDemuxerEFvRKNS_17RepeatingCallbackIFvNS3_14PipelineStatusEEEEiEJNS_7WeakPtrIS4_EES8_EEEFviEE3RunEPNS0_13BindStateBaseEi
#15 0x000000d7f77e _ZNKR4base17RepeatingCallbackIFvN8remoting8protocol23ValidatingAuthenticator6ResultEEE3RunES4_
#16 0x000000d7e531 remoting::It2MeHost::OnConfirmationResult()
#17 0x000000d8be4f _ZN4base8internal13FunctorTraitsIMN8remoting9It2MeHostEFvRKNS_17RepeatingCallbackIFvNS2_8protocol23ValidatingAuthenticator6ResultEEEENS2_23It2MeConfirmationDialog6ResultEEvE6InvokeIPS3_JSB_SD_EEEvSF_OT_DpOT0_
#18 0x000000d8bdaa _ZN4base8internal12InvokeHelperILb0EvE8MakeItSoIRKMN8remoting9It2MeHostEFvRKNS_17RepeatingCallbackIFvNS4_8protocol23ValidatingAuthenticator6ResultEEEENS4_23It2MeConfirmationDialog6ResultEEJPS5_SD_SF_EEEvOT_DpOT0_
#19 0x000000d8bd1d _ZN4base8internal7InvokerINS0_9BindStateIMN8remoting9It2MeHostEFvRKNS_17RepeatingCallbackIFvNS3_8protocol23ValidatingAuthenticator6ResultEEEENS3_23It2MeConfirmationDialog6ResultEEJNS0_17UnretainedWrapperIS4_EESA_EEEFvSE_EE7RunImplIRKSG_RKNSt3__15tupleIJSI_SA_EEEJLm0ELm1EEEEvOT_OT0_NSP_16integer_sequenceImJXspT1_EEEEOSE_
#20 0x000000d8bc1b _ZN4base8internal7InvokerINS0_9BindStateIMN8remoting9It2MeHostEFvRKNS_17RepeatingCallbackIFvNS3_8protocol23ValidatingAuthenticator6ResultEEEENS3_23It2MeConfirmationDialog6ResultEEJNS0_17UnretainedWrapperIS4_EESA_EEEFvSE_EE3RunEPNS0_13BindStateBaseESE_
#21 0x000000d70c5f _ZNO4base17RepeatingCallbackIFvN8remoting23It2MeConfirmationDialog6ResultEEE3RunES3_
#22 0x000000d71699 remoting::It2MeConfirmationDialogProxy::ReportResult()
#23 0x000000d72ec1 _ZN4base8internal13FunctorTraitsIMN8remoting28It2MeConfirmationDialogProxyEFvNS2_23It2MeConfirmationDialog6ResultEEvE6InvokeIRKNS_7WeakPtrIS3_EEJRKS5_EEEvS7_OT_DpOT0_
#24 0x000000d72df5 _ZN4base8internal12InvokeHelperILb1EvE8MakeItSoIRKMN8remoting28It2MeConfirmationDialogProxyEFvNS4_23It2MeConfirmationDialog6ResultEERKNS_7WeakPtrIS5_EEJRKS7_EEEvOT_OT0_DpOT1_
#25 0x000000d72d6d _ZN4base8internal7InvokerINS0_9BindStateIMN8remoting28It2MeConfirmationDialogProxyEFvNS3_23It2MeConfirmationDialog6ResultEEJNS_7WeakPtrIS4_EES6_EEEFvvEE7RunImplIRKS8_RKNSt3__15tupleIJSA_S6_EEEJLm0ELm1EEEEvOT_OT0_NSH_16integer_sequenceImJXspT1_EEEE
#26 0x000000d72c7c _ZN4base8internal7InvokerINS0_9BindStateIMN8remoting28It2MeConfirmationDialogProxyEFvNS3_23It2MeConfirmationDialog6ResultEEJNS_7WeakPtrIS4_EES6_EEEFvvEE3RunEPNS0_13BindStateBaseE
#27 0x000001297b4e _ZNO4base12OnceCallbackIFvvEE3RunEv
#28 0x0000028d127f base::debug::TaskAnnotator::RunTask()
#29 0x0000028cbdf9 base::internal::IncomingTaskQueue::RunTask()
#30 0x0000028c9995 base::MessageLoop::RunTask()
#31 0x0000028c9c18 base::MessageLoop::DeferOrRunPendingTask()
#32 0x0000028c9f49 base::MessageLoop::DoWork()
#33 0x0000028d4b1e base::MessagePumpLibevent::Run()
#34 0x0000028c915c base::MessageLoop::Run()
#35 0x00000294caad base::RunLoop::Run()
#36 0x000000f41d12 remoting::AutoThread::ThreadMain()
#37 0x0000029de99d base::(anonymous namespace)::ThreadFunc()
#38 0x7fc9f87ad494 start_thread
#39 0x7fc9f25c0a8f clone