Refactor how shapes are done

As part of Wayland support, we should hold the shape and opaque regions
on the MetaWindow rather than fetching them in the MetaWindowActor, as
this gives us better flexibility as to where the regions are set, and
allows for easier Wayland support.

To make merging easier with the Wayland branch, we also append the _x11
suffix to functions that use the X SHAPE extension to fetch the shaped
regions.

https://bugzilla.gnome.org/show_bug.cgi?id=706930

src/core/window-private.h

@@ -325,9 +325,6 @@ struct _MetaWindow
   guint using_net_wm_icon_name         : 1; /* vs. plain wm_icon_name */
   guint using_net_wm_visible_icon_name : 1; /* tracked so we can clear it */
 
-  /* has a shape mask */
-  guint has_shape : 1;
-
   /* icon props have changed */
   guint need_reread_icon : 1;
   
@@ -349,6 +346,9 @@ struct _MetaWindow
   /* if non-NULL, the bounds of the window frame */
   cairo_region_t *frame_bounds;
 
+  /* if non-NULL, the bounding shape region of the window */
+  cairo_region_t *shape_region;
+
   /* if non-NULL, the opaque region _NET_WM_OPAQUE_REGION */
   cairo_region_t *opaque_region;
 
@@ -665,7 +665,6 @@ void meta_window_update_icon_now (MetaWindow *window);
 
 void meta_window_update_role (MetaWindow *window);
 void meta_window_update_net_wm_type (MetaWindow *window);
-void meta_window_update_opaque_region (MetaWindow *window);
 void meta_window_update_for_monitors_changed (MetaWindow *window);
 void meta_window_update_on_all_workspaces (MetaWindow *window);
 
@@ -679,4 +678,12 @@ void meta_window_compute_tile_match (MetaWindow *window);
 
 gboolean meta_window_updates_are_frozen (MetaWindow *window);
 
+void meta_window_set_opaque_region        (MetaWindow     *window,
+                                           cairo_region_t *region);
+void meta_window_update_opaque_region_x11 (MetaWindow *window);
+
+void meta_window_set_shape_region         (MetaWindow     *window,
+                                           cairo_region_t *region);
+void meta_window_update_shape_region_x11  (MetaWindow *window);
+
 #endif