extend DrawingContext.cs to accept IGeometryImpl in DrawGeometry method

src/Avalonia.Visuals/Media/DrawingContext.cs

@@ -121,12 +121,23 @@ namespace Avalonia.Media
         /// <param name="pen">The stroke pen.</param>
         /// <param name="geometry">The geometry.</param>
         public void DrawGeometry(IBrush brush, IPen pen, Geometry geometry)
+        {
+            DrawGeometry(brush, pen, geometry.PlatformImpl);
+        }
+
+        /// <summary>
+        /// Draws a geometry.
+        /// </summary>
+        /// <param name="brush">The fill brush.</param>
+        /// <param name="pen">The stroke pen.</param>
+        /// <param name="geometry">The geometry.</param>
+        public void DrawGeometry(IBrush brush, IPen pen, IGeometryImpl geometry)
         {
             Contract.Requires<ArgumentNullException>(geometry != null);
 
             if (brush != null || PenIsVisible(pen))
             {
-                PlatformImpl.DrawGeometry(brush, pen, geometry.PlatformImpl);
+                PlatformImpl.DrawGeometry(brush, pen, geometry);
             }
         }