Remove AsyncError with Expando.

tests/standalone/io/http_redirect_test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
 
 import "package:expect/expect.dart";
 import "dart:async";
 import "dart:io";
 import "dart:uri";
 
@@ skipping 311 matching lines @@
       });
   });
 }
 
 void testAutoRedirectLimit() {
   setupServer().then((server) {
     HttpClient client = new HttpClient();
 
     client.getUrl(Uri.parse("http://127.0.0.1:${server.port}/1"))
       .then((HttpClientRequest request) => request.close())
-      .catchError((e) {
-        Expect.equals(5, e.error.redirects.length);
+      .catchError((error) {
+        Expect.equals(5, error.redirects.length);
         server.close();
         client.close();
       }, test: (e) => e is RedirectLimitExceededException);
   });
 }
 
 void testRedirectLoop() {
   setupServer().then((server) {
     HttpClient client = new HttpClient();
 
     int redirectCount = 0;
     client.getUrl(Uri.parse("http://127.0.0.1:${server.port}/A"))
       .then((HttpClientRequest request) => request.close())
-      .catchError((e) {
-        Expect.equals(2, e.error.redirects.length);
+      .catchError((error) {
+        Expect.equals(2, error.redirects.length);
         server.close();
         client.close();
       }, test: (e) => e is RedirectLoopException);
   });
 }
 
 void testRedirectClosingConnection() {
   setupServer().then((server) {
     HttpClient client = new HttpClient();
 
@@ skipping 15 matching lines @@
   testManualRedirect();
   testManualRedirectWithHeaders();
   testAutoRedirect();
   testAutoRedirectWithHeaders();
   testAutoRedirect301POST();
   testAutoRedirect303POST();
   testAutoRedirectLimit();
   testRedirectLoop();
   testRedirectClosingConnection();
 }