[SVG] SVGLength{,List} migration to new SVG property impl.

Source/core/svg/SVGImageElement.h

Index: Source/core/svg/SVGImageElement.h
diff --git a/Source/core/svg/SVGImageElement.h b/Source/core/svg/SVGImageElement.h
index 880208914cc7ac15f73d9d1957fbaa5342dd0f35..15fd0f089bdc941820c60c0f2fe9720f26244245 100644
--- a/Source/core/svg/SVGImageElement.h
+++ b/Source/core/svg/SVGImageElement.h
@@ -38,6 +38,11 @@ public:
 
     bool currentFrameHasSingleSecurityOrigin() const;
 
+    SVGAnimatedLength* x() const { return m_x.get(); }
+    SVGAnimatedLength* y() const { return m_y.get(); }
+    SVGAnimatedLength* width() const { return m_width.get(); }
+    SVGAnimatedLength* height() const { return m_height.get(); }
+
 private:
     explicit SVGImageElement(Document&);
 
@@ -63,11 +68,11 @@ private:
     virtual bool selfHasRelativeLengths() const;
     virtual void didMoveToNewDocument(Document& oldDocument) OVERRIDE;
 
+    RefPtr<SVGAnimatedLength> m_x;
+    RefPtr<SVGAnimatedLength> m_y;
+    RefPtr<SVGAnimatedLength> m_width;
+    RefPtr<SVGAnimatedLength> m_height;
     BEGIN_DECLARE_ANIMATED_PROPERTIES(SVGImageElement)
-        DECLARE_ANIMATED_LENGTH(X, x)
-        DECLARE_ANIMATED_LENGTH(Y, y)
-        DECLARE_ANIMATED_LENGTH(Width, width)
-        DECLARE_ANIMATED_LENGTH(Height, height)
         DECLARE_ANIMATED_PRESERVEASPECTRATIO(PreserveAspectRatio, preserveAspectRatio)
         DECLARE_ANIMATED_STRING(Href, href)
     END_DECLARE_ANIMATED_PROPERTIES