OTS: Adds more layout common table supports....

src/gdef.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef OTS_GDEF_H_
 #define OTS_GDEF_H_
 
 #include "ots.h"
 
 namespace ots {
 
 struct OpenTypeGDEF {
   OpenTypeGDEF()
       : version_2(false),
+        has_mark_attachment_class_def(false),
+        has_mark_glyph_sets_def(false),
+        num_mark_glyph_sets(0),
         data(NULL),
         length(0) {
   }
 
   bool version_2;
+  bool has_mark_attachment_class_def;
+  bool has_mark_glyph_sets_def;
+  uint16_t num_mark_glyph_sets;
+
   const uint8_t *data;
   size_t length;
 };
 
 }  // namespace ots
 
 #endif