Extend SkFontMgr_Custom to cover ttc, otf, pfb.

src/ports/SkFontHost_FreeType_common.h

Index: src/ports/SkFontHost_FreeType_common.h
diff --git a/src/ports/SkFontHost_FreeType_common.h b/src/ports/SkFontHost_FreeType_common.h
index 79e6d651631103642729c4788fc55f8b3bf2ec5b..226f55d45741bdd92663d2a7833c1a6e1ddba2c2 100644
--- a/src/ports/SkFontHost_FreeType_common.h
+++ b/src/ports/SkFontHost_FreeType_common.h
@@ -12,6 +12,7 @@
 #include "SkGlyph.h"
 #include "SkScalerContext.h"
 #include "SkTypeface.h"
+#include "SkTypes.h"
 
 #include <ft2build.h>
 #include FT_FREETYPE_H
@@ -48,8 +49,18 @@ public:
     /** For SkFontMgrs to make use of our ability to extract
      *  name and style from a stream, using FreeType's API.
      */
-    static bool ScanFont(SkStream* stream, int ttcIndex,
-                         SkString* name, SkFontStyle* style, bool* isFixedPitch);
+    class Scanner : ::SkNoncopyable {
+    public:
+        Scanner();
+        ~Scanner();
+        bool recognizedFont(SkStream* stream, int* numFonts) const;
+        bool scanFont(SkStream* stream, int ttcIndex,
+                      SkString* name, SkFontStyle* style, bool* isFixedPitch) const;
+    private:
+        FT_Face openFace(SkStream* stream, int ttcIndex, FT_Stream ftStream) const;
+        FT_Library fLibrary;
+        mutable SkMutex fLibraryMutex;
+    };
 
 protected:
     SkTypeface_FreeType(const SkFontStyle& style, SkFontID uniqueID, bool isFixedPitch)