Handle "url(...) none" and "url(...) currentColor" SVG paint specs

Source/core/svg/SVGPaint.h

Index: Source/core/svg/SVGPaint.h
diff --git a/Source/core/svg/SVGPaint.h b/Source/core/svg/SVGPaint.h
index f48b4b7ba0715f7cc02a5989d497ed790b1bd5b8..13a4769ba9153d5edb7071bf853b242c9e60ed63 100644
--- a/Source/core/svg/SVGPaint.h
+++ b/Source/core/svg/SVGPaint.h
@@ -86,6 +86,12 @@ public:
         return paint.release();
     }
 
+    static PassRefPtr<SVGPaint> createURIAndCurrentColor(const String& uri)
+    {
+        RefPtr<SVGPaint> paint = adoptRef(new SVGPaint(SVG_PAINTTYPE_URI_CURRENTCOLOR, uri));
+        return paint.release();
+    }
+
     const SVGPaintType& paintType() const { return m_paintType; }
     String uri() const { return m_uri; }