Fix type warnings in API and helpers.

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 126 matching lines @@
       // It's already mapped, use it.
       return _session;
     }
     // Create session, store it in connection, and return.
     return _session = _httpServer._sessionManager.createSession();
   }
 
   HttpConnectionInfo get connectionInfo => _httpConnection.connectionInfo;
 
   X509Certificate get certificate {
-    Socket socket = _httpConnection._socket;
+    var socket = _httpConnection._socket;
     if (socket is SecureSocket) return socket.peerCertificate;
     return null;
   }
 }
 
 
 class _HttpClientResponse
     extends _HttpInboundMessage implements HttpClientResponse {
   List<RedirectInfo> get redirects => _httpRequest._responseRedirects;
 
@@ skipping 2077 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;
 }