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

Source/core/svg/SVGUseElement.h

Index: Source/core/svg/SVGUseElement.h
diff --git a/Source/core/svg/SVGUseElement.h b/Source/core/svg/SVGUseElement.h
index 800af8f7c80491d66fdfa045c9217483a3edbcff..7f55a49caac3bf82ea2a938eede126c2e90a0372 100644
--- a/Source/core/svg/SVGUseElement.h
+++ b/Source/core/svg/SVGUseElement.h
@@ -50,6 +50,11 @@ public:
 
     RenderObject* rendererClipChild() 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:
     SVGUseElement(Document&, bool wasInsertedByParser);
 
@@ -96,11 +101,11 @@ private:
     void transferUseAttributesToReplacedElement(SVGElement* from, SVGElement* to) const;
     void transferEventListenersToShadowTree(SVGElementInstance* target);
 
+    RefPtr<SVGAnimatedLength> m_x;
+    RefPtr<SVGAnimatedLength> m_y;
+    RefPtr<SVGAnimatedLength> m_width;
+    RefPtr<SVGAnimatedLength> m_height;
     BEGIN_DECLARE_ANIMATED_PROPERTIES(SVGUseElement)
-        DECLARE_ANIMATED_LENGTH(X, x)
-        DECLARE_ANIMATED_LENGTH(Y, y)
-        DECLARE_ANIMATED_LENGTH(Width, width)
-        DECLARE_ANIMATED_LENGTH(Height, height)
         DECLARE_ANIMATED_STRING(Href, href)
         DECLARE_ANIMATED_BOOLEAN(ExternalResourcesRequired, externalResourcesRequired)
     END_DECLARE_ANIMATED_PROPERTIES