[subset] Skip glyph closure for any dropped table

If COLR or MATH tables are being dropped, there is no point in closing
glyphs over them, just like it is done for GSUB.

src/hb-subset-plan.cc

@@ -509,9 +509,7 @@ _glyf_add_gid_and_children (const OT::glyf_accelerator_t &glyf,
 
 static void
 _populate_gids_to_retain (hb_subset_plan_t* plan,
-			  bool close_over_gsub,
-			  bool close_over_gpos,
-			  bool close_over_gdef)
+		          hb_set_t* drop_tables)
 {
   OT::glyf_accelerator_t glyf (plan->source);
 #ifndef HB_NO_SUBSET_CFF
@@ -523,7 +521,7 @@ _populate_gids_to_retain (hb_subset_plan_t* plan,
   _cmap_closure (plan->source, plan->unicodes, plan->_glyphset_gsub);
 
 #ifndef HB_NO_SUBSET_LAYOUT
-  if (close_over_gsub)
+  if (!drop_tables->has (HB_OT_TAG_GSUB))
     // closure all glyphs/lookups/features needed for GSUB substitutions.
     _closure_glyphs_lookups_features<GSUB> (
         plan,
@@ -532,7 +530,7 @@ _populate_gids_to_retain (hb_subset_plan_t* plan,
         plan->gsub_features,
         plan->gsub_langsys);
 
-  if (close_over_gpos)
+  if (!drop_tables->has (HB_OT_TAG_GPOS))
     _closure_glyphs_lookups_features<GPOS> (
         plan,
         plan->_glyphset_gsub,
@@ -543,12 +541,18 @@ _populate_gids_to_retain (hb_subset_plan_t* plan,
   _remove_invalid_gids (plan->_glyphset_gsub, plan->source->get_num_glyphs ());
 
   hb_set_set (plan->_glyphset_mathed, plan->_glyphset_gsub);
-  _math_closure (plan, plan->_glyphset_mathed);
-  _remove_invalid_gids (plan->_glyphset_mathed, plan->source->get_num_glyphs ());
+  if (!drop_tables->has (HB_OT_TAG_MATH))
+  {
+    _math_closure (plan, plan->_glyphset_mathed);
+    _remove_invalid_gids (plan->_glyphset_mathed, plan->source->get_num_glyphs ());
+  }
 
   hb_set_t cur_glyphset = *plan->_glyphset_mathed;
-  _colr_closure (plan->source, plan->colrv1_layers, plan->colr_palettes, &cur_glyphset);
-  _remove_invalid_gids (&cur_glyphset, plan->source->get_num_glyphs ());
+  if (!drop_tables->has (HB_OT_TAG_COLR))
+  {
+    _colr_closure (plan->source, plan->colrv1_layers, plan->colr_palettes, &cur_glyphset);
+    _remove_invalid_gids (&cur_glyphset, plan->source->get_num_glyphs ());
+  }
 
   hb_set_set (plan->_glyphset_colred, &cur_glyphset);
 
@@ -570,7 +574,7 @@ _populate_gids_to_retain (hb_subset_plan_t* plan,
 
 
 #ifndef HB_NO_VAR
-  if (close_over_gdef)
+  if (!drop_tables->has (HB_OT_TAG_GDEF))
     _collect_layout_variation_indices (plan);
 #endif
 }
@@ -768,10 +772,7 @@ hb_subset_plan_create_or_fail (hb_face_t	 *face,
 
   _populate_unicodes_to_retain (input->sets.unicodes, input->sets.glyphs, plan);
 
-  _populate_gids_to_retain (plan,
-			    !input->sets.drop_tables->has (HB_OT_TAG_GSUB),
-			    !input->sets.drop_tables->has (HB_OT_TAG_GPOS),
-			    !input->sets.drop_tables->has (HB_OT_TAG_GDEF));
+  _populate_gids_to_retain (plan, input->sets.drop_tables);
 
   _create_old_gid_to_new_gid_map (face,
                                   input->flags & HB_SUBSET_FLAGS_RETAIN_GIDS,