Add missing certificate getter on HttpClientResponse and add a regression test.

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>> {
+class _HttpIncoming extends Stream<List<int>> {
   final int _transferLength;
   final Completer _dataCompleter = new Completer();
   Stream<List<int>> _stream;
 
   bool fullBodyRead = false;
 
   // Common properties.
   final _HttpHeaders headers;
   bool upgraded = false;
 
@@ skipping 28 matching lines @@
 
   // Is completed once all data have been received.
   Future get dataDone => _dataCompleter.future;
 
   void close() {
     fullBodyRead = true;
     _dataCompleter.complete();
   }
 }
 
-class _HttpInboundMessage extends Stream<List<int>> {
+abstract class _HttpInboundMessage extends Stream<List<int>> {
   final _HttpIncoming _incoming;
   List<Cookie> _cookies;
 
   _HttpInboundMessage(_HttpIncoming this._incoming);
 
   List<Cookie> get cookies {
     if (_cookies != null) return _cookies;
     return _cookies = headers._parseCookies();
   }
 
-  HttpHeaders get headers => _incoming.headers;
+  _HttpHeaders get headers => _incoming.headers;
   String get protocolVersion => headers.protocolVersion;
   int get contentLength => headers.contentLength;
   bool get persistentConnection => headers.persistentConnection;
 }
 
 
 class _HttpRequest extends _HttpInboundMessage implements HttpRequest {
   final HttpResponse response;
 
   // Lazy initialized parsed query parameters.
   Map<String, String> _queryParameters;
 
   final _HttpServer _httpServer;
 
   final _HttpConnection _httpConnection;
 
-  HttpSession _session;
+  _HttpSession _session;
 
   _HttpRequest(_HttpResponse this.response,
                _HttpIncoming _incoming,
                _HttpServer this._httpServer,
                _HttpConnection this._httpConnection)
       : super(_incoming) {
     response.headers.persistentConnection = headers.persistentConnection;
 
     if (_httpServer._sessionManagerInstance != null) {
       // Map to session if exists.
@@ skipping 64 matching lines @@
   List<Cookie> _cookies;
 
   _HttpClientResponse(_HttpIncoming _incoming,
                       _HttpClientRequest this._httpRequest,
                       _HttpClient this._httpClient)
       : super(_incoming);
 
   int get statusCode => _incoming.statusCode;
   String get reasonPhrase => _incoming.reasonPhrase;
 
+  X509Certificate get certificate {
+    var socket = _httpRequest._httpClientConnection._socket;
+    return socket.peerCertificate;
+  }
+
   List<Cookie> get cookies {
     if (_cookies != null) return _cookies;
     _cookies = new List<Cookie>();
     List<String> values = headers[HttpHeaders.SET_COOKIE];
     if (values != null) {
       values.forEach((value) {
         _cookies.add(new Cookie.fromSetCookieValue(value));
       });
     }
     return _cookies;
@@ skipping 1421 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;
 }