Fix dart2js analyze _api_test for dart:io

sdk/lib/io/http_impl.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.
 
 part of dart.io;
 
 class _HttpIncoming
     extends Stream<List<int>> implements StreamSink<List<int>> {
   final int _transferLength;
   final Completer _dataCompleter = new Completer();
@@ skipping 1579 matching lines @@
   }
 
   void authorize(HttpClientRequest request) {
     credentials.authorize(this, request);
     used = true;
   }
 
   bool used = false;
   Uri uri;
   String realm;
-  HttpClientCredentials credentials;
+  _HttpClientCredentials credentials;
 
   // Digest specific fields.
   String nonce;
   String algorithm;
   String qop;
 }
 
 
 abstract class _HttpClientCredentials implements HttpClientCredentials {
   _AuthenticationScheme get scheme;
-  void authorize(HttpClientRequest request);
+  void authorize(_Credentials credentials, HttpClientRequest request);
 }
 
 
 class _HttpClientBasicCredentials implements HttpClientBasicCredentials {
   _HttpClientBasicCredentials(this.username,
                               this.password);
 
   _AuthenticationScheme get scheme => _AuthenticationScheme.BASIC;
 
   void authorize(_Credentials _, HttpClientRequest request) {
@@ skipping 30 matching lines @@
 
 
 class _RedirectInfo implements RedirectInfo {
   const _RedirectInfo(int this.statusCode,
                       String this.method,
                       Uri this.location);
   final int statusCode;
   final String method;
   final Uri location;
 }