remove some redundant casts

@@ -9,17 +9,13 @@ final class MediaTrackConstraintsDelegate {
 
 
   /// Get the settings for the given [mediaStream].
   /// Get the settings for the given [mediaStream].
   MediaTrackSettings? getSettings(MediaStream? mediaStream) {
   MediaTrackSettings? getSettings(MediaStream? mediaStream) {
-    final List<JSAny?>? tracks = mediaStream?.getVideoTracks().toDart;
+    final List<MediaStreamTrack>? tracks = mediaStream?.getVideoTracks().toDart;
 
 
     if (tracks == null || tracks.isEmpty) {
     if (tracks == null || tracks.isEmpty) {
       return null;
       return null;
     }
     }
 
 
-    final MediaStreamTrack? track = tracks.first as MediaStreamTrack?;
-
-    if (track == null) {
-      return null;
-    }
+    final MediaStreamTrack track = tracks.first;
 
 
     final MediaTrackCapabilities capabilities = track.getCapabilities();
     final MediaTrackCapabilities capabilities = track.getCapabilities();
     final MediaTrackSettings settings = track.getSettings();
     final MediaTrackSettings settings = track.getSettings();

@@ -115,8 +115,8 @@ final class ZXingBarcodeReader extends BarcodeReader {
   ) async {
   ) async {
     final JSPromise? result = _reader?.attachStreamToVideo.callAsFunction(
     final JSPromise? result = _reader?.attachStreamToVideo.callAsFunction(
       _reader as JSAny?,
       _reader as JSAny?,
-      videoStream as JSAny,
-      videoElement as JSAny,
+      videoStream,
+      videoElement,
     ) as JSPromise?;
     ) as JSPromise?;
 
 
     await result?.toDart;
     await result?.toDart;
@@ -136,7 +136,7 @@ final class ZXingBarcodeReader extends BarcodeReader {
     controller.onListen = () {
     controller.onListen = () {
       _reader?.decodeContinuously.callAsFunction(
       _reader?.decodeContinuously.callAsFunction(
         _reader as JSAny?,
         _reader as JSAny?,
-        _reader?.videoElement as JSAny?,
+        _reader?.videoElement,
         (Result? result, JSAny? error) {
         (Result? result, JSAny? error) {
           if (controller.isClosed || result == null) {
           if (controller.isClosed || result == null) {
             return;
             return;