Enabled custom renderer factory for X11 and macOS

src/Avalonia.Native/WindowImplBase.cs

@@ -300,7 +300,15 @@ namespace Avalonia.Native
         public IRenderer CreateRenderer(IRenderRoot root)
         {
             if (_deferredRendering)
-                return new DeferredRenderer(root, AvaloniaLocator.Current.GetService<IRenderLoop>());
+            {
+                var loop = AvaloniaLocator.Current.GetService<IRenderLoop>();
+                var customRendererFactory = AvaloniaLocator.Current.GetService<IRendererFactory>();
+
+                if (customRendererFactory != null)
+                    return customRendererFactory.Create(root, loop);
+                return new DeferredRenderer(root, loop);
+            }
+
             return new ImmediateRenderer(root);
         }
 

src/Avalonia.X11/X11Window.cs

@@ -331,6 +331,11 @@ namespace Avalonia.X11
         public IRenderer CreateRenderer(IRenderRoot root)
         {
             var loop = AvaloniaLocator.Current.GetService<IRenderLoop>();
+            var customRendererFactory = AvaloniaLocator.Current.GetService<IRendererFactory>();
+
+            if (customRendererFactory != null)
+                return customRendererFactory.Create(root, loop);
+            
             return _platform.Options.UseDeferredRendering ?
                 new DeferredRenderer(root, loop) :
                 (IRenderer)new X11ImmediateRendererProxy(root, loop);