Split out String, URI and CustomIdent from CSSPrimitiveValue

Source/core/css/CSSValuePool.cpp

Index: Source/core/css/CSSValuePool.cpp
diff --git a/Source/core/css/CSSValuePool.cpp b/Source/core/css/CSSValuePool.cpp
index a1c3183a69b4e3d6ff801f01427f1b80d377b400..73699311feea99f92e4921460fcb6092d2065a60 100644
--- a/Source/core/css/CSSValuePool.cpp
+++ b/Source/core/css/CSSValuePool.cpp
@@ -26,6 +26,7 @@
 #include "config.h"
 #include "core/css/CSSValuePool.h"
 
+#include "core/css/CSSStringValue.h"
 #include "core/css/CSSValueList.h"
 #include "core/css/parser/CSSParser.h"
 #include "core/style/ComputedStyle.h"
@@ -126,11 +127,11 @@ PassRefPtrWillBeRawPtr<CSSPrimitiveValue> CSSValuePool::createValue(const Length
     return CSSPrimitiveValue::create(value, style.effectiveZoom());
 }
 
-PassRefPtrWillBeRawPtr<CSSPrimitiveValue> CSSValuePool::createFontFamilyValue(const String& familyName)
+PassRefPtrWillBeRawPtr<CSSStringValue> CSSValuePool::createFontFamilyValue(const String& familyName)
 {
-    RefPtrWillBeMember<CSSPrimitiveValue>& value = m_fontFamilyValueCache.add(familyName, nullptr).storedValue->value;
+    RefPtrWillBeMember<CSSStringValue>& value = m_fontFamilyValueCache.add(familyName, nullptr).storedValue->value;
     if (!value)
-        value = CSSPrimitiveValue::create(familyName, CSSPrimitiveValue::UnitType::CustomIdentifier);
+        value = CSSStringValue::create(familyName, CSSStringValue::SerializeAsCustomIdentifier);
     return value;
 }