Remove AsyncError with Expando.

pkg/scheduled_test/lib/src/scheduled_server/safe_http_server.dart

Index: pkg/scheduled_test/lib/src/scheduled_server/safe_http_server.dart
diff --git a/pkg/scheduled_test/lib/src/scheduled_server/safe_http_server.dart b/pkg/scheduled_test/lib/src/scheduled_server/safe_http_server.dart
index a75add40fe03703d5195459caa6ed2e244e1f843..59b2d07b7070de945594a2d1839f8adb2dea9418 100644
--- a/pkg/scheduled_test/lib/src/scheduled_server/safe_http_server.dart
+++ b/pkg/scheduled_test/lib/src/scheduled_server/safe_http_server.dart
@@ -42,13 +42,12 @@ class SafeHttpServer extends StreamView<HttpRequest> implements HttpServer {
   HttpConnectionsInfo connectionsInfo() => _inner.connectionsInfo();
 
   StreamSubscription<HttpRequest> listen(void onData(HttpRequest value),
-      {void onError(AsyncError error), void onDone(),
+      {void onError(error), void onDone(),
       bool unsubscribeOnError: false}) {
     var subscription;
     subscription = super.listen((request) {
       onData(new _HttpRequestWrapper(request));
-    }, onError: (e) {
-      var error = e.error;
+    }, onError: (error) {
       // Ignore socket error 104, which is caused by a request being cancelled
       // before it writes any headers. There's no reason to care about such
       // requests.