[ot] Make sure all toplevel tables have tableTag

src/hb-open-file-private.hh

@@ -197,6 +197,8 @@ struct TTCHeader
 
 struct OpenTypeFontFile
 {
+  static const hb_tag_t tableTag	= HB_TAG ('_','_','_','_'); /* Sanitizer needs this. */
+
   static const hb_tag_t CFFTag		= HB_TAG ('O','T','T','O'); /* OpenType with Postscript outlines */
   static const hb_tag_t TrueTypeTag	= HB_TAG ( 0 , 1 , 0 , 0 ); /* OpenType with TrueType outlines */
   static const hb_tag_t TTCTag		= HB_TAG ('t','t','c','f'); /* TrueType Collection */

src/hb-ot-hhea-table.hh

@@ -44,6 +44,8 @@ namespace OT {
 
 struct _hea
 {
+  static const hb_tag_t tableTag = HB_TAG('_','h','e','a');
+
   static const hb_tag_t hheaTag	= HB_OT_TAG_hhea;
   static const hb_tag_t vheaTag	= HB_OT_TAG_vhea;
 

src/hb-ot-hmtx-table.hh

@@ -52,6 +52,8 @@ struct LongMetric
 
 struct _mtx
 {
+  static const hb_tag_t tableTag = HB_TAG('_','m','t','x');
+
   static const hb_tag_t hmtxTag	= HB_OT_TAG_hmtx;
   static const hb_tag_t vmtxTag	= HB_OT_TAG_vmtx;