Chrome OS: Crash touch-dragging a window between "displays" on linux-chromeos

This is a low priority issue, I'm not sure it could ever occur on a real device.
(AFAIK, no existing device/display config allows touch-dragging across displays)

On linux-chromeos ToT @ #605711
(1) Run with two "displays" and a simulated touch device (get id from "xinput list")
    chrome --ash-host-window-bounds=500x500,500+0-700x700 --touch-devices=10 --show-taps
(2) Drag a window between the displays using the simulated touch device
Expected: Window drags fine, no crash.
Actual: Crash! Stack below.

[258115:258115:1108/102323.988773:FATAL:window_event_dispatcher.cc(591)] Check failed: window()->Contains(target_window). 
#0 0x7fc04025c44f base::debug::StackTrace::StackTrace()
#1 0x7fc04018ce3b logging::LogMessage::~LogMessage()
#2 0x7fc03b6017c9 aura::WindowEventDispatcher::PreDispatchEvent()
#3 0x7fc03bc1f796 ui::EventDispatcherDelegate::DispatchEvent()
#4 0x7fc03b6003ca aura::WindowEventDispatcher::ProcessGestures()
#5 0x7fc03b6026ca aura::WindowEventDispatcher::PostDispatchEvent()
#6 0x7fc03bc1f7d8 ui::EventDispatcherDelegate::DispatchEvent()
#7 0x7fc03bc214c2 ui::EventProcessor::OnEventFromSource()
#8 0x7fc03bc21a8e ui::EventSource::SendEventToSinkFromRewriter()
#9 0x7fc039998964 ash::AshWindowTreeHostPlatform::DispatchEventFromQueue()
#10 0x7fc02fa5953f ws::HostEventQueue::DispatchOrQueueEvent()
#11 0x7fc03bc2654a ui::DispatchEventFromNativeUiEvent()
#12 0x7fc03932597e ui::X11WindowOzone::DispatchEvent()
#13 0x7fc03f2f6923 ui::PlatformEventSource::DispatchEvent()
#14 0x7fc02f7e0c79 ui::X11EventSourceLibevent::DispatchPlatformEvent()
#15 0x7fc02f7e0721 ui::X11EventSourceLibevent::ProcessXEvent()
#16 0x7fc02f7dbae1 ui::X11EventSource::DispatchXEvents()
#17 0x7fc04027f902 base::MessagePumpLibevent::OnLibeventNotification()
#18 0x7fc040296ecd event_base_loop
#19 0x7fc04027fb1e base::MessagePumpLibevent::Run()
#20 0x7fc04019bff4 base::MessageLoopImpl::Run()
#21 0x7fc0401cdca9 base::RunLoop::Run()
#22 0x556990889dcd ChromeBrowserMainParts::MainMessageLoopRun()
#23 0x7fc03d100fc7 content::BrowserMainLoop::RunMainMessageLoopParts()
#24 0x7fc03d103b26 content::BrowserMainRunnerImpl::Run()
#25 0x7fc03d0fd569 content::BrowserMain()
#26 0x7fc03dbc8e3b content::ContentMainRunnerImpl::RunServiceManager()
#27 0x7fc03dbc8d07 content::ContentMainRunnerImpl::Run()
#28 0x7fc03065aec6 service_manager::Main()
#29 0x7fc03dbc7204 content::ContentMain()
#30 0x55698fa6b783 ChromeMain
#31 0x7fc030c1a2b1 __libc_start_main
#32 0x55698fa6b5fa _start