Add .address to [Raw]ServerSocket and HttpServer.

sdk/lib/io/http_impl.dart

Index: sdk/lib/io/http_impl.dart
diff --git a/sdk/lib/io/http_impl.dart b/sdk/lib/io/http_impl.dart
index 99c2806b20663570396c16061ba4e46351bd5815..fcaf191978a2e9d573269c189b15e72a8bed21f6 100644
--- a/sdk/lib/io/http_impl.dart
+++ b/sdk/lib/io/http_impl.dart
@@ -2012,6 +2012,11 @@ class _HttpServer extends Stream<HttpRequest> implements HttpServer {
     return _serverSocket.port;
   }
 
+  InternetAddress get address {
+    if (closed) throw new HttpException("HttpServer is not bound to a socket");
+    return _serverSocket.address;
+  }
+
   set sessionTimeout(int timeout) {
     _sessionManager.sessionTimeout = timeout;
   }