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

Source/core/style/StyleGeneratedImage.h

Index: Source/core/style/StyleGeneratedImage.h
diff --git a/Source/core/style/StyleGeneratedImage.h b/Source/core/style/StyleGeneratedImage.h
index a372eefeb4e4259f653c4f92d49ca8169a2d15bc..7541c311961c793cb3bbe245cce2e57147a79e4b 100644
--- a/Source/core/style/StyleGeneratedImage.h
+++ b/Source/core/style/StyleGeneratedImage.h
@@ -40,7 +40,7 @@ public:
 
     virtual WrappedImagePtr data() const override { return m_imageGeneratorValue.get(); }
 
-    virtual PassRefPtrWillBeRawPtr<CSSValue> cssValue() const override;
+    virtual CSSValue cssValue() const override;
 
     virtual LayoutSize imageSize(const LayoutObject*, float multiplier) const override;
     virtual bool imageHasRelativeWidth() const override { return !m_fixedSize; }