wayland: Fix segfault when trying to set cursor without input

[17567:17567:0528/100616:ERROR:display.cc(227)] Not implemented reached in virtual void ozonewayland::WaylandDisplay::SetWidgetState(unsigned int, ui::WidgetState, unsigned int, unsigned int) SHOW 1
[17567:17606:0528/100616:WARNING:server_connection_manager.cc(296)] ServerConnectionManager forcing SYNC_AUTH_ERROR
[17567:17606:0528/100616:WARNING:syncer_proto_util.cc(277)] Error posting from syncer: Response Code (bogus on error): -1 Content-Length (bogus on error): -1 Server Status: SYNC_AUTH_ERROR
[17567:17606:0528/100616:ERROR:get_updates_processor.cc(240)] PostClientToServerMessage() failed during GetUpdates
[17567:17584:0528/100617:WARNING:backend_impl.cc(1780)] Destroying invalid entry.
[17567:17567:0528/100616:FATAL:input_device.cc(216)] Check failed: input_pointer_.
 #0 0x7f9f01fd0a99 base::debug::StackTrace::StackTrace()
 #1 0x7f9f02022a33 logging::LogMessage::~LogMessage()
 #2 0x7f9f03337610 ozonewayland::WaylandInputDevice::SetCursorType()
 #3 0x7f9f0332f9c8 ozonewayland::WaylandDisplay::SetWidgetCursor()
 #4 0x7f9f06f07869 views::DesktopWindowTreeHostWayland::SetCursorNative()
 #5 0x7f9f033238ad aura::WindowTreeHost::SetCursor()
 #6 0x7f9f06f1da8d views::DesktopNativeCursorManager::SetCursor()
 #7 0x7f9f06dcdf5c wm::CursorManager::SetCursor()
 #8 0x7f9f06dc94d8 wm::CompoundEventFilter::UpdateCursor()
 #9 0x7f9f06dc99bf wm::CompoundEventFilter::OnMouseEvent()
 #10 0x7f9f086c0093 ui::EventHandler::OnEvent()
 #11 0x7f9f086bdcf1 ui::EventDispatcher::DispatchEvent()
 #12 0x7f9f086bdab7 ui::EventDispatcher::DispatchEventToEventHandlers()
 #13 0x7f9f086bd79d ui::EventDispatcher::ProcessEvent()
 #14 0x7f9f086bd476 ui::EventDispatcherDelegate::DispatchEventToTarget()
 #15 0x7f9f086bd33d ui::EventDispatcherDelegate::DispatchEvent()
 #16 0x7f9f0331bcbf aura::WindowEventDispatcher::DispatchMouseEnterOrExit()
 #17 0x7f9f0331dde1 aura::WindowEventDispatcher::PreDispatchMouseEvent()
 #18 0x7f9f0331c5c1 aura::WindowEventDispatcher::PreDispatchEvent()
 #19 0x7f9f086bd2dd ui::EventDispatcherDelegate::DispatchEvent()
 #20 0x7f9f086c15e7 ui::EventProcessor::OnEventFromSource()
 #21 0x7f9f0331d845 aura::WindowEventDispatcher::SynthesizeMouseMoveEvent()
 #22 0x7f9f0331fe00 base::internal::RunnableAdapter<>::Run()
 #23 0x7f9f0331fc87 base::internal::InvokeHelper<>::MakeItSo()
 #24 0x7f9f0331fab8 base::internal::Invoker<>::Run()
 #25 0x7f9f00e1beb9 base::Callback<>::Run()
 #26 0x7f9f02033288 base::MessageLoop::RunTask()
 #27 0x7f9f020333ac base::MessageLoop::DeferOrRunPendingTask()
 #28 0x7f9f020338d3 base::MessageLoop::DoWork()
 #29 0x7f9f01fb45ef base::MessagePumpLibevent::Run()
 #30 0x7f9f02032dd7 base::MessageLoop::RunHandler()
 #31 0x7f9f0207300a base::RunLoop::Run()
 #32 0x7f9f01678366 ChromeBrowserMainParts::MainMessageLoopRun()
 #33 0x7f9f05851634 content::BrowserMainLoop::RunMainMessageLoopParts()
 #34 0x7f9f058589dc content::BrowserMainRunnerImpl::Run()
 #35 0x7f9f0584dba8 content::BrowserMain()
 #36 0x7f9f01f73f75 content::RunNamedProcessTypeMain()
 #37 0x7f9f01f74fa1 content::ContentMainRunnerImpl::Run()
 #38 0x7f9f01f73439 content::ContentMain()
 #39 0x7f9f00d75344 ChromeMain
 #40 0x7f9f00d752ea main
 #41 0x7f9efcbc876d __libc_start_main
 #42 0x7f9f00d751f9 <unknown>