Add hb_face_get_upem()

src/hb-font.cc

@@ -397,6 +397,12 @@ hb_face_get_table (hb_face_t *face,
   return blob;
 }
 
+unsigned int
+hb_face_get_upem (hb_face_t *face)
+{
+  return (face->head_table ? face->head_table : &Null(head))->get_upem ();
+}
+
 
 /*
  * hb_font_t

src/hb-font.h

@@ -78,6 +78,9 @@ hb_blob_t *
 hb_face_get_table (hb_face_t *face,
 		   hb_tag_t   tag);
 
+unsigned int
+hb_face_get_upem (hb_face_t *face);
+
 
 /*
  * hb_font_funcs_t