Fix errors in previous commit

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>> {
   final int _transferLength;
   final Completer _dataCompleter = new Completer();
   Stream<List<int>> _stream;
@@ skipping 1923 matching lines @@
   String host;
   int port;
   String realm;
   _HttpClientCredentials credentials;
 }
 
 
 abstract class _HttpClientCredentials implements HttpClientCredentials {
   _AuthenticationScheme get scheme;
   void authorize(_Credentials credentials, HttpClientRequest request);
+  void authorizeProxy(_ProxyCredentials _, HttpClientRequest request);
 }
 
 
 class _HttpClientBasicCredentials
     extends _HttpClientCredentials
     implements HttpClientBasicCredentials {
   _HttpClientBasicCredentials(this.username,
                               this.password);
 
   _AuthenticationScheme get scheme => _AuthenticationScheme.BASIC;
@@ skipping 47 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;
 }