Add parseFontFaceDescriptor for @font-face handling

Source/core/css/StyleRule.h

Index: Source/core/css/StyleRule.h
diff --git a/Source/core/css/StyleRule.h b/Source/core/css/StyleRule.h
index 062b5b517848fea6da06297030ed7d34d65bf54c..570a5ca46c9e030f8a91e79ec74d4b7acd19c9b0 100644
--- a/Source/core/css/StyleRule.h
+++ b/Source/core/css/StyleRule.h
@@ -44,12 +44,12 @@ public:
         Style,
         Import,
         Media,
-        FontFace,
         Page,
         Keyframes,
         Keyframe,
         Namespace,
         Supports,
+        FontFace,
         Viewport,
     };
 
@@ -141,7 +141,7 @@ public:
     const StylePropertySet& properties() const { return *m_properties; }
     MutableStylePropertySet& mutableProperties();
 
-    void setProperties(PassRefPtrWillBeRawPtr<StylePropertySet>);
+    bool setProperties(PassRefPtrWillBeRawPtr<StylePropertySet>);
 
     PassRefPtrWillBeRawPtr<StyleRuleFontFace> copy() const { return adoptRefWillBeNoop(new StyleRuleFontFace(*this)); }