compositor: add a way to disable picking of client surfaces

Surfaces like drag'n'drop icons shouldn't receive events as a normal
surface but are still created by the client so add a way for the
compositor to enable or disable the picking of a client surface.

Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>

src/compositor.c

@@ -544,7 +544,7 @@ weston_compositor_pick_surface(struct weston_compositor *compositor,
 	struct weston_surface *surface;
 
 	wl_list_for_each(surface, &compositor->surface_list, link) {
-		if (surface->surface.resource.client == NULL)
+		if (!surface->pickable)
 			continue;
 		weston_surface_from_global(surface, x, y, sx, sy);
 		if (0 <= *sx && *sx < surface->geometry.width &&
@@ -1270,6 +1270,8 @@ compositor_create_surface(struct wl_client *client,
 		(void (**)(void)) &surface_interface;
 	surface->surface.resource.data = surface;
 
+	surface->pickable = 1;
+
 	wl_client_add_resource(client, &surface->surface.resource);
 }
 

src/compositor.h

@@ -251,6 +251,7 @@ struct weston_surface {
 	uint32_t alpha;
 	uint32_t visual;
 	int overlapped;
+	int pickable;
 
 	/* Surface geometry state, mutable.
 	 * If you change anything, set dirty = 1.