Add parseFontFaceDescriptor for @font-face handling

Source/core/css/parser/CSSParser.h

Index: Source/core/css/parser/CSSParser.h
diff --git a/Source/core/css/parser/CSSParser.h b/Source/core/css/parser/CSSParser.h
index d6037eb192290a0c5e1ee2c601ce344fece539e0..9b0fec5296ee42c8eed982803afb66c96869ce97 100644
--- a/Source/core/css/parser/CSSParser.h
+++ b/Source/core/css/parser/CSSParser.h
@@ -40,6 +40,8 @@ public:
     // This is for non-shorthands only
     static PassRefPtrWillBeRawPtr<CSSValue> parseSingleValue(CSSPropertyID, const String&, const CSSParserContext& = strictCSSParserContext());
 
+    static PassRefPtrWillBeRawPtr<CSSValue> parseFontFaceDescriptor(CSSPropertyID, const String&, const CSSParserContext&);
+
     static PassRefPtrWillBeRawPtr<ImmutableStylePropertySet> parseInlineStyleDeclaration(const String&, Element*);
 
     static PassOwnPtr<Vector<double>> parseKeyframeKeyList(const String&);