Split out String, URI and CustomIdent from CSSPrimitiveValue

Source/core/css/FontFace.cpp

Index: Source/core/css/FontFace.cpp
diff --git a/Source/core/css/FontFace.cpp b/Source/core/css/FontFace.cpp
index 0d7ce68af047895fbb4990aa04d659debf436d70..afc9e091a605e58f881375971644a2b9ead2904c 100644
--- a/Source/core/css/FontFace.cpp
+++ b/Source/core/css/FontFace.cpp
@@ -40,6 +40,7 @@
 #include "core/css/CSSFontFaceSrcValue.h"
 #include "core/css/CSSFontSelector.h"
 #include "core/css/CSSPrimitiveValue.h"
+#include "core/css/CSSStringValue.h"
 #include "core/css/CSSUnicodeRangeValue.h"
 #include "core/css/CSSValueList.h"
 #include "core/css/FontFaceDescriptors.h"
@@ -276,14 +277,14 @@ bool FontFace::setFamilyValue(CSSValueList* familyList)
     if (familyList->length() != 1)
         return false;
 
-    CSSPrimitiveValue* familyValue = toCSSPrimitiveValue(familyList->item(0));
+    CSSValue* familyValue = familyList->item(0);
     AtomicString family;
-    if (familyValue->isCustomIdent()) {
-        family = AtomicString(familyValue->getStringValue());
-    } else if (familyValue->isValueID()) {
+    if (familyValue->isStringValue() && toCSSStringValue(familyValue)->serializationType() == CSSStringValue::SerializeAsCustomIdentifier) {
+        family = AtomicString(toCSSStringValue(familyValue)->getStringValue());
+    } else if (familyValue->isPrimitiveValue() && toCSSPrimitiveValue(familyValue)->isValueID()) {
         // We need to use the raw text for all the generic family types, since @font-face is a way of actually
         // defining what font to use for those types.
-        switch (familyValue->getValueID()) {
+        switch (toCSSPrimitiveValue(familyValue)->getValueID()) {
         case CSSValueSerif:
             family =  FontFamilyNames::webkit_serif;
             break;