Move most of the [Pass]RefPtr's of CSSPrimitiveValue to our transition types.

Source/core/css/CSSCrossfadeValue.h

 /*
  * Copyright (C) 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 43 matching lines @@
 
     PassRefPtr<Image> image(RenderObject*, const IntSize&);
     bool isFixedSize() const { return true; }
     IntSize fixedSize(const RenderObject*);
 
     bool isPending() const;
     bool knownToBeOpaque(const RenderObject*) const;
 
     void loadSubimages(ResourceFetcher*);
 
-    void setPercentage(PassRefPtr<CSSPrimitiveValue> percentageValue) { m_percentageValue = percentageValue; }
+    void setPercentage(PassRefPtrWillBeRawPtr<CSSPrimitiveValue> percentageValue) { m_percentageValue = percentageValue; }
 
     bool hasFailedOrCanceledSubresources() const;
 
     bool equals(const CSSCrossfadeValue&) const;
 
     void traceAfterDispatch(Visitor*);
 
 private:
     CSSCrossfadeValue(PassRefPtr<CSSValue> fromValue, PassRefPtr<CSSValue> toValue)
         : CSSImageGeneratorValue(CrossfadeClass)
@@ skipping 14 matching lines @@
         void setReady(bool ready) { m_ready = ready; }
     private:
         CSSCrossfadeValue* m_ownerValue;
         bool m_ready;
     };
 
     void crossfadeChanged(const IntRect&);
 
     RefPtr<CSSValue> m_fromValue;
     RefPtr<CSSValue> m_toValue;
-    RefPtr<CSSPrimitiveValue> m_percentageValue;
+    RefPtrWillBeMember<CSSPrimitiveValue> m_percentageValue;
 
     ResourcePtr<ImageResource> m_cachedFromImage;
     ResourcePtr<ImageResource> m_cachedToImage;
 
     RefPtr<Image> m_generatedImage;
 
     CrossfadeSubimageObserverProxy m_crossfadeSubimageObserver;
 };
 
 DEFINE_CSS_VALUE_TYPE_CASTS(CSSCrossfadeValue, isCrossfadeValue());
 
 } // namespace WebCore
 
 #endif // CSSCrossfadeValue_h