Add 'uri' to HttpException, and include in toString.

sdk/lib/io/http.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;
 
 /**
  * HTTP status codes.
  */
 abstract class HttpStatus {
@@ skipping 1381 matching lines @@
  * this class.
  */
 abstract class DetachedSocket {
   Socket get socket;
   List<int> get unparsedData;
 }
 
 
 class HttpException implements IOException {
   final String message;
+  final Uri uri;
 
-  const HttpException([String this.message = ""]);
+  const HttpException(String this.message, {Uri this.uri});
 
-  String toString() => "HttpException: $message";
+  String toString() {
+    var b = new StringBuffer();
+    b.write('HttpException: ');
+    b.write(message);
+    if (uri != null) {
+      b.write(', uri = $uri');
+    }
+    return b.toString();
+  }
 }
 
 
 class RedirectException implements HttpException {
   final String message;
   final List<RedirectInfo> redirects;
 
   const RedirectException(String this.message,
                           List<RedirectInfo> this.redirects);
 
   String toString() => "RedirectException: $message";
 }