Bug 1360309 - Work around some broken Apple fonts. r=jrmuizel

gfx/thebes/gfxMacPlatformFontList.mm

@@ -216,6 +216,15 @@ MacOSFontEntry::ReadCMAP(FontInfoData *aFontInfoData)
                 charmap->ClearRange(sr->rangeStart, sr->rangeEnd);
             }
         }
+
+        // Bug 1360309: several of Apple's Chinese fonts have spurious blank
+        // glyphs for obscure Tibetan codepoints. Blacklist these so that font
+        // fallback will not use them.
+        if (mRequiresAAT && (FamilyName().EqualsLiteral("Songti SC") ||
+                             FamilyName().EqualsLiteral("Songti TC") ||
+                             FamilyName().EqualsLiteral("STSong"))) {
+            charmap->ClearRange(0x0f8c, 0x0f8f);
+        }
     }
 
     mHasCmapTable = NS_SUCCEEDED(rv);