Add the ability to get info of a Http connection, e.g. host and port.

runtime/bin/http_impl.dart

 // Copyright (c) 2012, 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.
 
 class _HttpHeaders implements HttpHeaders {
   _HttpHeaders() : _headers = new Map<String, List<String>>();
 
   List<String> operator[](String name) {
     name = name.toLowerCase();
     return _headers[name];
@@ skipping 689 matching lines @@
     }
   }
 
   void _updateContentLength(int bytes) {
     if (_bodyBytesWritten + bytes > _contentLength) {
       throw new HttpException("Writing more than specified content length");
     }
     _bodyBytesWritten += bytes;
   }
 
+  HttpConnectionInfo get connectionInfo() => _httpConnection.connectionInfo;
+
   int _state;
   bool _headResponse;
 
   _HttpConnectionBase _httpConnection;
   _HttpHeaders _headers;
   List<Cookie> _cookies;
   String _protocolVersion = "1.1";
 
   // Length of the content body. If this is set to -1 (default value)
   // when starting to send data chunked transfer encoding will be
@@ skipping 514 matching lines @@
     _socket.onData = null;
     _socket.onClosed = null;
     _socket.onError = null;
     _socket.outputStream.onNoPendingWrites = null;
     Socket socket = _socket;
     _socket = null;
     if (onDetach != null) onDetach();
     return new _DetachedSocket(socket, _httpParser.unparsedData);
   }
 
+  HttpConnectionInfo get connectionInfo() {
+    if (_socket == null || _closing || _error) return null;
+    try {
+      _HttpConnectionInfo info = new _HttpConnectionInfo();
+      info.remoteHost = _socket.remoteHost;
+      info.remotePort = _socket.remotePort;
+      info.localPort = _socket.port;
+      return info;
+    } catch (var e) { }
+    return null;
+  }
+
   abstract void _onConnectionClosed(e);
   abstract void _responseDone();
 
   void set _onNoPendingWrites(void callback()) {
     if (!_error) {
       _socket.outputStream.onNoPendingWrites = callback;
     }
   }
 
   int hashCode() => _hashCode;
@@ skipping 839 matching lines @@
   }
 
   Function _onOpen;
   Map<String, Queue<_SocketConnection>> _openSockets;
   Set<_SocketConnection> _activeSockets;
   Timer _evictionTimer;
   bool _shutdown;  // Has this HTTP client been shutdown?
 }
 
 
+class _HttpConnectionInfo implements HttpConnectionInfo {
+  String remoteHost;
+  int remotePort;
+  int localPort;
+}
+
+
 class _DetachedSocket implements DetachedSocket {
   _DetachedSocket(this._socket, this._unparsedData);
   Socket get socket() => _socket;
   List<int> get unparsedData() => _unparsedData;
   Socket _socket;
   List<int> _unparsedData;
 }
 
 
 class _RedirectInfo implements RedirectInfo {
   const _RedirectInfo(int this.statusCode,
                       String this.method,
                       Uri this.location);
   final int statusCode;
   final String method;
   final Uri location;
 }