ivi-shell: add API for weston_surface -> ivi_layout_surface

Add ivi-layout API for getting an ivi_layout_surface from a
weston_surface if it exists. This can be used by controllers that hook
up to core Weston callbacks and get handed a weston_surface, but need to
use ivi-layout API to manipulate it.

The only ways ivi-layout itself would be able to go from weston_surface
to ivi_layout_surface are either searching through the list of all
ivi_layout_surfaces or adding a dummy destroy listener to the
weston_surface. Therefore the implementation is delegated to
ivi-shell.c.

Ivi-shell.c can easily look up the ivi_shell_surface for a
weston_surface, and that will map 1:1 to an ivi_layout_surface.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Reviewed-by: Emre Ucan <eucan@de.adit-jv.com>
diff --git a/ivi-shell/ivi-shell.c b/ivi-shell/ivi-shell.c
index c502c74..59ffe0c 100644
--- a/ivi-shell/ivi-shell.c
+++ b/ivi-shell/ivi-shell.c
@@ -93,6 +93,18 @@
 	return shsurf;
 }
 
+struct ivi_layout_surface *
+shell_get_ivi_layout_surface(struct weston_surface *surface)
+{
+	struct ivi_shell_surface *shsurf;
+
+	shsurf = get_ivi_shell_surface(surface);
+	if (!shsurf)
+		return NULL;
+
+	return shsurf->layout_surface;
+}
+
 void
 shell_surface_send_configure(struct weston_surface *surface,
 			     int32_t width, int32_t height)