CSSValue Immediates: Change CSSValue to an object instead of a pointer

Source/core/css/parser/CSSParserFastPaths.h

Index: Source/core/css/parser/CSSParserFastPaths.h
diff --git a/Source/core/css/parser/CSSParserFastPaths.h b/Source/core/css/parser/CSSParserFastPaths.h
index 1b3a31b3a721d4436364a00e9f0d10dc83d7cc3c..405b47f017ea937b3013215490f4720bd3ce508c 100644
--- a/Source/core/css/parser/CSSParserFastPaths.h
+++ b/Source/core/css/parser/CSSParserFastPaths.h
@@ -12,13 +12,13 @@
 
 namespace blink {
 
-class CSSValue;
+class NullableCSSValue;
 
 class CSSParserFastPaths {
 public:
     // Parses simple values like '10px' or 'green', but makes no guarantees
     // about handling any property completely.
-    static PassRefPtrWillBeRawPtr<CSSValue> maybeParseValue(CSSPropertyID, const String&, CSSParserMode);
+    static NullableCSSValue maybeParseValue(CSSPropertyID, const String&, CSSParserMode);
 
     // Properties handled here shouldn't be explicitly handled in CSSPropertyParser
     static bool isKeywordPropertyID(CSSPropertyID);