backends: Get rid of meta-cursor-private.h

There is nothing special about the private API which only consists of
getters for renderer specific backing buffer. Lets them to the regular
.h file and treat them as part of the normal API.

https://bugzilla.gnome.org/show_bug.cgi?id=744932

src/backends/meta-cursor.c

@@ -21,7 +21,7 @@
 
 #include "config.h"
 
-#include "meta-cursor-private.h"
+#include "meta-cursor.h"
 
 #include <meta/errors.h>
 
@@ -30,6 +30,7 @@
 #include "meta-backend-private.h"
 
 #ifdef HAVE_NATIVE_BACKEND
+#include <gbm.h>
 #include "backends/native/meta-cursor-renderer-native.h"
 #endif
 
@@ -43,6 +44,27 @@
 #include <cogl/cogl-wayland-server.h>
 #endif
 
+typedef struct
+{
+  CoglTexture2D *texture;
+  int hot_x, hot_y;
+
+#ifdef HAVE_NATIVE_BACKEND
+  struct gbm_bo *bo;
+#endif
+} MetaCursorImage;
+
+struct _MetaCursorSprite
+{
+  GObject parent;
+
+  MetaCursor cursor;
+  MetaCursorImage image;
+
+  int current_frame;
+  XcursorImages *xcursor_images;
+};
+
 GType meta_cursor_sprite_get_type (void) G_GNUC_CONST;
 
 G_DEFINE_TYPE (MetaCursorSprite, meta_cursor_sprite, G_TYPE_OBJECT)