pango: Use CoglMaterial type for materials

Instead of using the CoglHandle type for material variables this updates
the pango code to use CoglMaterial * instead. CoglHandle is the old
typename which is being phased out of the API.

pango/cogl-pango-display-list.h

@@ -58,8 +58,8 @@ void _cogl_pango_display_list_add_trapezoid (CoglPangoDisplayList *dl,
 
 void _cogl_pango_display_list_render (CoglPangoDisplayList *dl,
                                       const CoglColor *color,
-                                      CoglHandle glyph_material,
-                                      CoglHandle solid_material);
+                                      CoglMaterial *glyph_material,
+                                      CoglMaterial *solid_material);
 
 void _cogl_pango_display_list_clear (CoglPangoDisplayList *dl);