mash: Crash opening ARC++ app

After working around the startup crashes in  Issue 761148 :
(1) Run chrome --mash on a device that supports ARC.
(2) Try to run an ARC++ app.
Expected: ARC++ app starts up.
Actual: Crash! (stack below)

Received signal 11 SEGV_MAPERR 0000000000b0
#0 0x5c35d937976c base::debug::StackTrace::StackTrace()
#1 0x5c35d93792c1 base::debug::(anonymous namespace)::StackDumpSignalHandler()
#2 0x749d84b942e0 <unknown>
#3 0x5c35da46d3d9 aura::Window::AddChild()
#4 0x5c35d86bf010 exo::Pointer::UpdatePointerSurface()
#5 0x5c35d86beeda exo::Pointer::SetCursor()
#6 0x5c35d874fdf8 exo::wayland::(anonymous namespace)::pointer_set_cursor()
#7 0x749d840b0e24 ffi_call_unix64
#8 0x749d840b053b ffi_call
#9 0x5c35db7f1958 wl_closure_invoke
#10 0x5c35db7ef2fb wl_client_connection_data
#11 0x5c35db7ee703 wl_event_loop_dispatch
#12 0x5c35d874a859 exo::wayland::Server::Dispatch()
#13 0x5c35dc447954 ExoParts::WaylandWatcher::OnFileCanReadWithoutBlocking()
#14 0x5c35d9396829 base::MessagePumpLibevent::OnLibeventNotification()
#15 0x5c35d942112c event_base_loop
#16 0x5c35d9396b55 base::MessagePumpLibevent::Run()
#17 0x5c35d93b7b46 base::RunLoop::Run()
#18 0x5c35d9046048 ChromeBrowserMainParts::MainMessageLoopRun()
#19 0x5c35d7c771c4 content::BrowserMainLoop::RunMainMessageLoopParts()
#20 0x5c35d7c79c12 content::BrowserMainRunnerImpl::Run()
#21 0x5c35d7c72a0c content::BrowserMain()
#22 0x5c35d9019f4c content::ContentMainRunnerImpl::Run()
#23 0x5c35d903b8df service_manager::Main()
#24 0x5c35d9018e01 content::ContentMain()
#25 0x5c35d75ed8f5 ChromeMain
#26 0x749d83a0c736 __libc_start_main
#27 0x5c35d75ed6d9 _start
  r8: 0000000000000000  r9: 0000749d83466780 r10: 473a3a73754d7265 r11: 0000000000000000
 r12: 00003fa0c64ddc60 r13: 0000000000000000 r14: 0000000000000000 r15: 00003fa0c7c3ab00
  di: 00007ffd16874100  si: 00003fa0c64e3968  bp: 00007ffd16874260  bx: 0000000000000000
  dx: 00003fa0c64e3968  ax: 9cc91fc24fbf3100  cx: 00003fa0c64e3960  sp: 00007ffd168741b0
  ip: 00005c35da46d3d9 efl: 0000000000010246 cgf: 0000000000000033 erf: 0000000000000004
 trp: 000000000000000e msk: 0000000000000000 cr2: 00000000000000b0
[end of stack trace]

This is blocking my work... I might take a look soon, but I'm not sure I'll get to this in the next week or two.