Oops, forgot to add nop version on ios/android

Author: wareya

examples/util/fill.rs

@@ -178,6 +178,14 @@ mod platform {
         // No-op on mobile platforms.
     }
 
+    #[allow(dead_code)]
+    pub fn fill_window_with_fn(
+        window: &dyn winit::window::Window,
+        f: impl FnOnce(&mut [u32], usize, f64, u32, u32) -> Vec<[u32; 4]>,
+    ) {
+        // No-op on mobile platforms.
+    }
+
     #[allow(dead_code)]
     pub fn fill_window_with_animated_color(
         _window: &dyn winit::window::Window,