The tryjob in question is http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_x64_rel_ng/builds/369741, and the CL is https://codereview.chromium.org/2704133002/#ps20001. The CL in question shouldn't affect input at all, so I'm surprised that it randomly failed here. It would be nice if we could figure out what's going on, to avoid random test flakiness.

(I'm not sure if there's a good way to search test logs...)

[4284:4348:0220/021026.183:FATAL:pointereventfactory.cpp(276)] Check failed: mouseEvent.id == coalescedMouseEvent.id (0 vs. 2147483647)
Backtrace:
	base::debug::StackTrace::StackTrace [0x0000000141620435+69]
	base::debug::StackTrace::StackTrace [0x00000001415E2BE3+19]
	logging::LogMessage::~LogMessage [0x000000014157E62A+74]
	blink::PointerEventFactory::create [0x0000000143EC45A5+1045]
	blink::PointerEventManager::sendMousePointerEvent [0x000000014408345D+93]
	blink::EventHandler::handleMouseMoveOrLeaveEvent [0x00000001440725B4+1252]
	blink::EventHandler::handleMouseMoveEvent [0x000000014407200D+189]
	blink::PageWidgetEventHandler::handleMouseMove [0x0000000143A10E13+83]
	blink::PageWidgetDelegate::handleInputEvent [0x0000000143A10BF7+711]
	blink::WebFrameWidgetImpl::handleInputEvent [0x00000001455F2910+1104]
	content::RenderWidgetInputHandler::HandleInputEvent [0x0000000144935AB5+1093]
	content::RenderWidget::OnHandleInputEvent [0x000000014487C31C+60]
	IPC::DispatchToMethod<content::RenderWidget,void (__cdecl content::RenderWidget::*)(blink::WebInputEvent const * __ptr64,std::vector<blink::WebInputEvent const * __ptr64,std::allocator<blink::WebInputEvent const * __ptr64> > const & __ptr64,ui::LatencyInf [0x000000014483DF08+88]
	IPC::MessageT<InputMsg_HandleInputEvent_Meta,std::tuple<blink::WebInputEvent const * __ptr64,std::vector<blink::WebInputEvent const * __ptr64,std::allocator<blink::WebInputEvent const * __ptr64> >,ui::LatencyInfo,enum content::InputEventDispatchType>,void [0x0000000144877665+261]
	content::RenderWidget::OnMessageReceived [0x000000014487D0FB+2059]
	IPC::MessageRouter::RouteMessage [0x0000000144F3EA84+52]
	IPC::MessageRouter::OnMessageReceived [0x0000000144F3EA32+50]
	content::ChildThreadImpl::OnMessageReceived [0x0000000143746421+225]
	base::internal::Invoker<base::internal::BindState<void (__cdecl VersionHandler::*)(std::vector<content::WebPluginInfo,std::allocator<content::WebPluginInfo> > const & __ptr64) __ptr64,base::WeakPtr<VersionHandler> >,void __cdecl(std::vector<content::WebPl [0x000000014331A3B6+70]
	content::InputEventFilter::HandleEventOnMainThread [0x00000001448FE5A5+277]
	content::MainThreadEventQueue::DispatchInFlightEvent [0x0000000144972212+754]
	content::MainThreadEventQueue::DispatchRafAlignedInput [0x000000014497241D+429]
	content::InputEventFilter::ProcessRafAlignedInput [0x00000001448FEC6D+253]
	content::RenderWidget::BeginMainFrame [0x0000000144879653+51]
	cc::ProxyMain::BeginMainFrame [0x0000000142941437+1319]
	base::internal::Invoker<base::internal::BindState<void (__cdecl cc::ProxyMain::*)(std::unique_ptr<cc::BeginMainFrameAndCommitState,std::default_delete<cc::BeginMainFrameAndCommitState> >) __ptr64,base::WeakPtr<cc::ProxyMain>,base::internal::PassedWrapper< [0x000000014295CBC2+162]
	base::debug::TaskAnnotator::RunTask [0x000000014162A5A0+416]
	blink::scheduler::TaskQueueManager::ProcessTaskFromWorkQueue [0x000000014396FA41+1249]
	blink::scheduler::TaskQueueManager::DoWork [0x000000014396E41E+798]
	base::internal::InvokeHelper<1,void>::MakeItSo<void (__cdecl content::WebMediaPlayerMS::*const & __ptr64)(bool) __ptr64,base::WeakPtr<content::WebMediaPlayerMS> const & __ptr64,bool const & __ptr64> [0x0000000143246AED+93]
	base::debug::TaskAnnotator::RunTask [0x000000014162A5A0+416]
	base::MessageLoop::RunTask [0x000000014159162E+1294]
	base::MessageLoop::DoWork [0x0000000141590400+400]
	base::MessagePumpDefault::Run [0x000000014162CC12+242]
	base::RunLoop::Run [0x000000014158D351+161]
	content::RendererMain [0x000000014484734E+670]
	content::RunNamedProcessTypeMain [0x00000001415620F9+265]
	content::ContentMainRunnerImpl::Run [0x0000000141561F8D+365]
	content::ContentMain [0x0000000141561420+48]
	content::LaunchTests [0x0000000141BE0BF5+661]
	LaunchChromeTests [0x0000000144D192CE+94]
	main [0x0000000144D18F4F+83]
	__scrt_common_main_seh [0x0000000144CB8009+285] (f:\ddctools\crtcstartup\src\startup\exe_common.inl:253)
	BaseThreadInitThunk [0x00000000776759BD+13]
	RtlUserThreadStart [0x00000000778AA2E1+33]