device: Make InputDevice an object and subclass it for X11

ClutterInputDevice should be a type that we can subclass per-backend
to add functionality.

clutter/clutter-event.h

@@ -29,6 +29,7 @@
 #define __CLUTTER_EVENT_H__
 
 #include <glib-object.h>
+#include <clutter/clutter-input-device.h>
 #include <clutter/clutter-types.h>
 
 #define CLUTTER_TYPE_EVENT	(clutter_event_get_type ())
@@ -201,37 +202,6 @@ typedef struct _ClutterScrollEvent      ClutterScrollEvent;
 typedef struct _ClutterStageStateEvent  ClutterStageStateEvent;
 typedef struct _ClutterCrossingEvent    ClutterCrossingEvent;
 
-/**
- * ClutterInputDevice:
- *
- * Generic representation of an input device. The
- * actual contents of this structure depend on the
- * backend used.
- */
-typedef struct _ClutterInputDevice      ClutterInputDevice;
-
-/**
- * ClutterInputDeviceType:
- * @CLUTTER_POINTER_DEVICE: A pointer device
- * @CLUTTER_KEYBOARD_DEVICE: A keyboard device
- * @CLUTTER_EXTENSION_DEVICE: A generic extension device
- * @CLUTTER_N_DEVICE_TYPES: The number of device types
- *
- * The types of input devices available.
- *
- * The #ClutterInputDeviceType enumeration can be extended at later
- * date; not every platform supports every input device type.
- *
- * Since: 1.0
- */
-typedef enum {
-  CLUTTER_POINTER_DEVICE,
-  CLUTTER_KEYBOARD_DEVICE,
-  CLUTTER_EXTENSION_DEVICE,
-
-  CLUTTER_N_DEVICE_TYPES
-} ClutterInputDeviceType;
-
 /**
  * ClutterAnyEvent:
  * @type: event type
@@ -509,9 +479,6 @@ guint32                clutter_keysym_to_unicode            (guint             k
 guint32                clutter_get_current_event_time       (void);
 G_CONST_RETURN ClutterEvent *clutter_get_current_event      (void);
 
-ClutterInputDeviceType clutter_input_device_get_device_type (ClutterInputDevice *device);
-gint                   clutter_input_device_get_device_id   (ClutterInputDevice *device);
-
 G_END_DECLS
 
 #endif /* __CLUTTER_EVENT_H__ */