[gtk+] gtk-demo: Handle GDK_TOUCH_CANCEL in event-axes demo

[Carlos Garnacho <carlosg src gnome org>]

commit 6fd05dfe53ae68a3730a0dc3461bb044de4a1ca3
Author: Carlos Garnacho <carlosg gnome org>
Date:   Mon Mar 14 15:28:20 2016 +0100

    gtk-demo: Handle GDK_TOUCH_CANCEL in event-axes demo
    
    It is a thing in wayland, which means we leave traces from older
    touches when the compositor takes over touch sequences in order
    to handle a gesture.

 demos/gtk-demo/event_axes.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/demos/gtk-demo/event_axes.c b/demos/gtk-demo/event_axes.c
index bc31f53..bfec8b7 100644
--- a/demos/gtk-demo/event_axes.c
+++ b/demos/gtk-demo/event_axes.c
@@ -131,7 +131,8 @@ update_axes_from_event (GdkEvent  *event,
   source_device = gdk_event_get_source_device (event);
   sequence = gdk_event_get_event_sequence (event);
 
-  if (event->type == GDK_TOUCH_END)
+  if (event->type == GDK_TOUCH_END ||
+      event->type == GDK_TOUCH_CANCEL)
     {
       g_hash_table_remove (data->touch_info, sequence);
       return;