View::OnTouchEvent NOTREACHED hit on linux-chromeos login

On a linux-chromeos debug build on ToT @ #624881
1. Run "xinput list" to get the id of a mouse to simulate touch (8).
2. Run "chrome --touch-devices=8 --login-manager" (with an account already added)
3. Use the mouse to simulate tapping on the login background view.
Expected: touch input is handled correctly.
Actual: NOTREACHED() crash, callstack below.

This doesn't repro if you skip --login-manager or login and then use touch.

[209946:209946:0122/130416.313312:FATAL:view.cc(1050)] Check failed: false. Views should not receive touch events.
#0 0x7f701ff69dcf base::debug::StackTrace::StackTrace()
#1 0x7f701fe980ea logging::LogMessage::~LogMessage()
#2 0x7f7019a5d5c0 views::View::OnTouchEvent()
#3 0x7f701b9140c2 ui::EventDispatcher::DispatchEventToEventHandlers()
#4 0x7f701b913cbc ui::EventDispatcher::ProcessEvent()
#5 0x7f701b913b89 ui::EventDispatcherDelegate::DispatchEventToTarget()
#6 0x7f701b913ae0 ui::EventDispatcherDelegate::DispatchEvent()
#7 0x7f701b915832 ui::EventProcessor::OnEventFromSource()
#8 0x7f700efc8f67 ws::EventQueue::DeliverOrQueueEvent()
#9 0x7f70191c2c0a ash::AshWindowTreeHostPlatform::DeliverEventToSink()
#10 0x7f701b915dd8 ui::EventSource::SendEventToSinkFromRewriter()
#11 0x7f701b21687e aura::WindowTreeHostPlatform::DispatchEvent()
#12 0x7f70191c2ac8 ash::AshWindowTreeHostPlatform::DispatchEvent()
#13 0x7f701b91a7ca ui::DispatchEventFromNativeUiEvent()
#14 0x7f7018d5272e ui::X11WindowOzone::DispatchEvent()
#15 0x7f701f014a83 ui::PlatformEventSource::DispatchEvent()
#16 0x7f700ed77ad9 ui::X11EventSourceLibevent::DispatchPlatformEvent()
#17 0x7f700ed77591 ui::X11EventSourceLibevent::ProcessXEvent()
#18 0x7f700ed729d0 ui::X11EventSource::DispatchXEvents()
#19 0x7f701ff8cd7c base::MessagePumpLibevent::OnLibeventNotification()
#20 0x7f701ffa435d event_base_loop
#21 0x7f701ff8cf1e base::MessagePumpLibevent::Run()
#22 0x7f701fea6ea8 base::MessageLoopImpl::Run()
#23 0x7f701fed8125 base::RunLoop::Run()
#24 0x555c699a0beb ChromeBrowserMainParts::MainMessageLoopRun()
#25 0x7f701cdc4f94 content::BrowserMainLoop::RunMainMessageLoopParts()
#26 0x7f701cdc7656 content::BrowserMainRunnerImpl::Run()
#27 0x7f701cdc1bbc content::BrowserMain()
#28 0x7f701d8a3cbc content::ContentMainRunnerImpl::RunServiceManager()
#29 0x7f701d8a38c1 content::ContentMainRunnerImpl::Run()
#30 0x7f700fc5d4e3 service_manager::Main()
#31 0x7f701d8a1d24 content::ContentMain()
#32 0x555c68b21e23 ChromeMain
#33 0x7f70101952b1 __libc_start_main
#34 0x555c68b21c9a _start