Remove filename from SkFontDescriptor.

include/core/SkPicture.h

Index: include/core/SkPicture.h
diff --git a/include/core/SkPicture.h b/include/core/SkPicture.h
index f514828e56148e00c9f6dd5ad5f768ee2e4df773..8a6216e1aa14092a9ed12b1b9c0c095bb01b2a89 100644
--- a/include/core/SkPicture.h
+++ b/include/core/SkPicture.h
@@ -253,6 +253,9 @@ private:
     static const uint32_t MIN_PICTURE_VERSION = 35;     // Produced by Chrome M39.
     static const uint32_t CURRENT_PICTURE_VERSION = 41;
 
+    static_assert(MIN_PICTURE_VERSION <= 41,
+                  "Remove kFontFileName and related code from SkFontDescriptor.cpp.");
+
     void createHeader(SkPictInfo* info) const;
     static bool IsValidPictInfo(const SkPictInfo& info);