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

Source/core/css/resolver/ElementStyleResources.h

Index: Source/core/css/resolver/ElementStyleResources.h
diff --git a/Source/core/css/resolver/ElementStyleResources.h b/Source/core/css/resolver/ElementStyleResources.h
index 3a0cdda374c84bbcffe826596012108e735c2fed..4d29e539e52a9c18fc34948b185ecdf6fff711ca 100644
--- a/Source/core/css/resolver/ElementStyleResources.h
+++ b/Source/core/css/resolver/ElementStyleResources.h
@@ -38,11 +38,12 @@ class CSSImageSetValue;
 class CSSSVGDocumentValue;
 class CSSValue;
 class FilterOperation;
+class NullableCSSValue;
 class StyleImage;
 class TextLinkColors;
 
 typedef WillBeHeapHashMap<RawPtrWillBeMember<FilterOperation>, RefPtrWillBeMember<CSSSVGDocumentValue>> PendingSVGDocumentMap;
-typedef WillBeHeapHashMap<CSSPropertyID, RefPtrWillBeMember<CSSValue>> PendingImagePropertyMap;
+typedef WillBeHeapHashMap<CSSPropertyID, NullableCSSValue> PendingImagePropertyMap;
 
 // Holds information about resources, requested by stylesheets.
 // Lifetime: per-element style resolve.
@@ -52,12 +53,12 @@ class ElementStyleResources {
 public:
     ElementStyleResources();
 
-    PassRefPtr<StyleImage> styleImage(Document&, const TextLinkColors&, Color currentColor, CSSPropertyID, CSSValue*);
+    PassRefPtr<StyleImage> styleImage(Document&, const TextLinkColors&, Color currentColor, CSSPropertyID, CSSValue);
 
     PassRefPtr<StyleImage> generatedOrPendingFromValue(CSSPropertyID, CSSImageGeneratorValue*);
-    PassRefPtr<StyleImage> cachedOrPendingFromValue(Document&, CSSPropertyID, CSSImageValue*);
-    PassRefPtr<StyleImage> setOrPendingFromValue(CSSPropertyID, CSSImageSetValue*);
-    PassRefPtr<StyleImage> cursorOrPendingFromValue(CSSPropertyID, CSSCursorImageValue*);
+    PassRefPtr<StyleImage> cachedOrPendingFromValue(Document&, CSSPropertyID, CSSImageValue&);
+    PassRefPtr<StyleImage> setOrPendingFromValue(CSSPropertyID, CSSImageSetValue&);
+    PassRefPtr<StyleImage> cursorOrPendingFromValue(CSSPropertyID, CSSCursorImageValue&);
 
     const PendingImagePropertyMap& pendingImageProperties() const { return m_pendingImageProperties; }
     const PendingSVGDocumentMap& pendingSVGDocuments() const { return m_pendingSVGDocuments; }