Generate toCSSFooValue() for CSSCursorImageValue and CSSFontFaceSrcValue

Source/core/css/CSSValue.cpp

Index: Source/core/css/CSSValue.cpp
diff --git a/Source/core/css/CSSValue.cpp b/Source/core/css/CSSValue.cpp
index 702590d817b250ac81221a7fbe6f284706ef1efe..19c9f20624c0b8a7c0c30316331c0b26b3e0f899 100644
--- a/Source/core/css/CSSValue.cpp
+++ b/Source/core/css/CSSValue.cpp
@@ -349,13 +349,13 @@ void CSSValue::destroy()
         delete static_cast<CSSCanvasValue*>(this);
         return;
     case CursorImageClass:
-        delete static_cast<CSSCursorImageValue*>(this);
+        delete toCSSCursorImageValue(this);
         return;
     case FontClass:
         delete static_cast<FontValue*>(this);
         return;
     case FontFaceSrcClass:
-        delete static_cast<CSSFontFaceSrcValue*>(this);
+        delete toCSSFontFaceSrcValue(this);
         return;
     case FontFeatureClass:
         delete static_cast<FontFeatureValue*>(this);