change readTypeface to return sk_sp

src/core/SkValidatingReadBuffer.h

Index: src/core/SkValidatingReadBuffer.h
diff --git a/src/core/SkValidatingReadBuffer.h b/src/core/SkValidatingReadBuffer.h
index d8575bdb4b56b71232387e25dc1e99cb0f02fe63..bad5f2fa93047021ecb238bec91b50808f801459 100644
--- a/src/core/SkValidatingReadBuffer.h
+++ b/src/core/SkValidatingReadBuffer.h
@@ -62,9 +62,6 @@ public:
     // helpers to get info about arrays and binary data
     uint32_t getArrayCount() override;
 
-    // TODO: Implement this (securely) when needed
-    SkTypeface* readTypeface() override;
-
     bool validate(bool isValid) override;
     bool isValid() const override;