Remove the type parameter from `SkObjectFinalizationRegistry`. (#21061)

lib/web_ui/lib/src/engine/canvaskit/canvaskit_api.dart

@@ -1640,7 +1640,7 @@ class TypefaceFontProviderNamespace {
 Timer? _skObjectCollector;
 List<SkDeletable> _skObjectDeleteQueue = <SkDeletable>[];
 
-final SkObjectFinalizationRegistry<SkDeletable> skObjectFinalizationRegistry = SkObjectFinalizationRegistry<SkDeletable>(js.allowInterop((SkDeletable deletable) {
+final SkObjectFinalizationRegistry skObjectFinalizationRegistry = SkObjectFinalizationRegistry(js.allowInterop((SkDeletable deletable) {
   _skObjectDeleteQueue.add(deletable);
   _skObjectCollector ??= _scheduleSkObjectCollection();
 }));
@@ -1673,8 +1673,6 @@ Timer _scheduleSkObjectCollection() => Timer(Duration.zero, () {
   html.window.performance.measure('SkObject collection', 'SkObject collection-start', 'SkObject collection-end');
 });
 
-typedef SkObjectFinalizer<T> = void Function(T key);
-
 /// Any Skia object that has a `delete` method.
 @JS()
 @anonymous
@@ -1698,8 +1696,10 @@ class SkDeletable {
 /// 5. The finalizer function is called with the SkPaint as the sole argument.
 /// 6. We call `delete` on SkPaint.
 @JS('window.FinalizationRegistry')
-class SkObjectFinalizationRegistry<T> {
-  external SkObjectFinalizationRegistry(SkObjectFinalizer<T> finalizer);
+class SkObjectFinalizationRegistry {
+  // TODO(hterkelsen): Add a type for the `cleanup` function when
+  // native constructors support type parameters.
+  external SkObjectFinalizationRegistry(Function cleanup);
   external void register(Object ckObject, Object skObject);
 }
 

lib/web_ui/lib/src/engine/canvaskit/skia_object_cache.dart

@@ -264,9 +264,8 @@ class SkiaObjectBox {
   bool _isDeleted = false;
 
   /// Deletes Skia objects when their wrappers are garbage collected.
-  static final SkObjectFinalizationRegistry<SkiaObjectBox> boxRegistry =
-      SkObjectFinalizationRegistry<SkiaObjectBox>(
-          js.allowInterop((SkiaObjectBox box) {
+  static final SkObjectFinalizationRegistry boxRegistry =
+      SkObjectFinalizationRegistry(js.allowInterop((SkiaObjectBox box) {
     box.delete();
   }));