Steps to repro:

1) Navigate to chrome://media-router
2) Refresh
3) Hit DCHECK with following stack trace:

[17176:17176:0309/132551:FATAL:issue_manager.cc(71)] Check failed: !issues_observers_.HasObserver(observer). 
#0 0x7fca76d74bde base::debug::StackTrace::StackTrace()
#1 0x7fca76db8c5f logging::LogMessage::~LogMessage()
#2 0x7fca7e6c5f4f media_router::IssueManager::RegisterObserver()
#3 0x7fca7e69d265 media_router::MediaRouterMojoImpl::RegisterIssuesObserver()
#4 0x7fca81c14dd8 media_router::IssuesObserver::RegisterObserver()
#5 0x7fca7e6fe18b media_router::MediaRouterUI::UIInitialized()
#6 0x7fca7e70d943 media_router::MediaRouterWebUIMessageHandler::OnRequestInitialData()
#7 0x7fca75f78de1 _ZN4base8internal15RunnableAdapterIM34PermissionBubbleMediaAccessHandlerFvPN7content11WebContentsEEE3RunIJRKS5_EEEvPS2_DpOT_
#8 0x7fca75f78d51 _ZN4base8internal12InvokeHelperILb0EvNS0_15RunnableAdapterIM34PermissionBubbleMediaAccessHandlerFvPN7content11WebContentsEEEEE8MakeItSoIJPS3_RKS6_EEEvS9_DpOT_
#9 0x7fca7e71381d _ZN4base8internal7InvokerINS_13IndexSequenceIJLm0EEEENS0_9BindStateINS0_15RunnableAdapterIMN12media_router30MediaRouterWebUIMessageHandlerEFvPKNS_9ListValueEEEEFvPS7_SA_EJNS0_17UnretainedWrapperIS7_EEEEENS0_12InvokeHelperILb0EvSD_EEFvRKSA_EE3RunEPNS0_13BindStateBaseESM_
#10 0x7fca75f3c8a6 base::Callback<>::Run()
#11 0x7fca7c163a06 content::WebUIImpl::ProcessWebUIMessage()
#12 0x7fca7c1625ab content::WebUIImpl::OnWebUISend()
#13 0x7fca7c138abb _ZN4base20DispatchToMethodImplIPN7content15WebContentsImplEMS2_FvRK4GURLRKSsRKNS_9ListValueEEJS4_SsS9_EJLm0ELm1ELm2EEEEvRKT_T0_RKSt5tupleIJDpT1_EENS_13IndexSequenceIJXspT2_EEEE
#14 0x7fca7c1389e5 _ZN4base16DispatchToMethodIPN7content15WebContentsImplEMS2_FvRK4GURLRKSsRKNS_9ListValueEEJS4_SsS9_EEEvRKT_T0_RKSt5tupleIJDpT1_EE
#15 0x7fca7c1650cf _ZN3IPC16DispatchToMethodIN7content9WebUIImplEMS2_FvRK4GURLRKSsRKN4base9ListValueEEvSt5tupleIJS3_SsS9_EEEEvPT_T0_PT1_RKT2_
#16 0x7fca7c164214 _ZN3IPC8MessageTI26ViewHostMsg_WebUISend_MetaSt5tupleIJ4GURLSsN4base9ListValueEEEvE8DispatchIN7content9WebUIImplESA_vMSA_FvRKS3_RKSsRKS5_EEEbPKNS_7MessageEPT_PT0_PT1_T2_
#17 0x7fca7c1623c2 content::WebUIImpl::OnMessageReceived()
#18 0x7fca7c111d91 content::WebContentsImpl::OnMessageReceived()
#19 0x7fca7c111c34 content::WebContentsImpl::OnMessageReceived()
#20 0x7fca7bf0013a content::RenderViewHostImpl::OnMessageReceived()
#21 0x7fca7bf10a03 content::RenderWidgetHostImpl::OnMessageReceived()
#22 0x7fca7bedea33 content::RenderProcessHostImpl::OnMessageReceived()
#23 0x7fca7840d8a3 IPC::ChannelProxy::Context::OnDispatchMessage()
#24 0x7fca75f40ff1 _ZN4base8internal15RunnableAdapterIM24WebRtcLoggingHandlerHostFvRKSsEE3RunIJS4_EEEvPS2_DpOT_
#25 0x7fca75f40f41 _ZN4base8internal12InvokeHelperILb0EvNS0_15RunnableAdapterIM24WebRtcLoggingHandlerHostFvRKSsEEEE8MakeItSoIJPS3_S5_EEEvS8_DpOT_
#26 0x7fca784119d0 _ZN4base8internal7InvokerINS_13IndexSequenceIJLm0ELm1EEEENS0_9BindStateINS0_15RunnableAdapterIMN3IPC12ChannelProxy7ContextEFvRKNS6_7MessageEEEEFvPS8_SB_EJSF_SB_EEENS0_12InvokeHelperILb0EvSE_EEFvvEE3RunEPNS0_13BindStateBaseE
#27 0x7fca75faa02e base::Callback<>::Run()
#28 0x7fca76ecd0ae base::debug::TaskAnnotator::RunTask()
#29 0x7fca76dccc1f base::MessageLoop::RunTask()
#30 0x7fca76dccea8 base::MessageLoop::DeferOrRunPendingTask()
#31 0x7fca76dcd072 base::MessageLoop::DoWork()
#32 0x7fca76ec8b56 base::MessagePumpGlib::Run()
#33 0x7fca76dcc64f base::MessageLoop::RunHandler()
#34 0x7fca76e23934 base::RunLoop::Run()
#35 0x7fca766f7d1f ChromeBrowserMainParts::MainMessageLoopRun()
#36 0x7fca7c331f39 content::BrowserMainLoop::RunMainMessageLoopParts()
#37 0x7fca7bc65ff5 content::BrowserMainRunnerImpl::Run()
#38 0x7fca7bc64c76 content::BrowserMain()
#39 0x7fca76ce7556 content::RunNamedProcessTypeMain()
#40 0x7fca76ce948d content::ContentMainRunnerImpl::Run()
#41 0x7fca76ce6ae2 content::ContentMain()
#42 0x7fca75e923f2 ChromeMain
#43 0x7fca75e923a2 main
#44 0x7fca6d24cec5 __libc_start_main
#45 0x7fca75e922a5 <unknown>