Move Image ownership out of CSSValue

Source/core/css/CSSCanvasValue.h

Index: Source/core/css/CSSCanvasValue.h
diff --git a/Source/core/css/CSSCanvasValue.h b/Source/core/css/CSSCanvasValue.h
index 4e15b7f9befe814fefd5542be805a764af347279..1c73714f595b1514acda619cc8902467200e0a61 100644
--- a/Source/core/css/CSSCanvasValue.h
+++ b/Source/core/css/CSSCanvasValue.h
@@ -47,8 +47,8 @@ public:
     bool isFixedSize() const { return true; }
     IntSize fixedSize(const LayoutObject*);
 
-    bool isPending() const { return false; }
-    void loadSubimages(Document*) { }
+    bool isPending(CSSStyleImageMap&) const { return false; }
+    void loadSubimages(Document*, CSSStyleImageMap&) { }
 
     bool equals(const CSSCanvasValue&) const;