dix: add TouchResourceIsOwner helper function

The first listener in the sequence is the owner of the touch sequence.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Chase Douglas <chase.douglas@canonical.com>

dix/touch.c

@@ -618,6 +618,16 @@ TouchGetPointerEventType(const InternalEvent *event)
 }
 
 
+/**
+ * @returns TRUE if the specified grab or selection is the current owner of
+ * the touch sequence.
+ */
+Bool
+TouchResourceIsOwner(TouchPointInfoPtr ti, XID resource)
+{
+    return (ti->listeners[0].listener == resource);
+}
+
 /**
  * Add the resource to this touch's listeners.
  */