dart:io | Replace duplicate implementation with Uri.resolveUri in HttpClient.

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 1550 matching lines @@
             return _getConnection(uri.host, port, proxyConf, isSecure)
                 .then(send);
           }
           return send(info);
         });
   }
 
   Future<HttpClientRequest> _openUrlFromRequest(String method,
                                                 Uri uri,
                                                 _HttpClientRequest previous) {
-    var u = uri;
     // If the new URI is relative (to either '/' or some sub-path),
     // construct a full URI from the previous one.
-    // See http://tools.ietf.org/html/rfc3986#section-4.2
-    replaceComponents({scheme, host, port, path}) {
-      uri = new Uri(
-          scheme: scheme != null ? scheme : uri.scheme,
-          host: host != null ? host : uri.host,
-          port: port != null ? port : uri.port,
-          path: path != null ? path : uri.path,
-          query: uri.query,
-          fragment: uri.fragment);
-    }
-
-    var scheme;
-    var host;
-    var port;
-    var path;
-    if (uri.host.isEmpty) {
-      host = previous.uri.host;
-      port = previous.uri.port;
-    }
-    if (uri.scheme.isEmpty) {
-      scheme = previous.uri.scheme;
-    }
-    if (!uri.path.startsWith('/')) {
-      var absolute = new _Path.raw(previous.uri.path).directoryPath;
-      absolute = absolute.join(new _Path.raw(u.path));
-      path = absolute.canonicalize().toString();
-    }
-    replaceComponents(scheme: scheme, host: host, port: port, path: path);
-    return openUrl(method, uri).then((_HttpClientRequest request) {
+    URI resolved = previous.uri.resolveUri(uri);
+    return openUrl(method, resolved).then((_HttpClientRequest request) {
           // Only follow redirects if initial request did.
           request.followRedirects = previous.followRedirects;
           // Allow same number of redirects.
           request.maxRedirects = previous.maxRedirects;
           // Copy headers.
           for (var header in previous.headers._headers.keys) {
             if (request.headers[header] == null) {
               request.headers.set(header, previous.headers[header]);
             }
           }
@@ skipping 862 matching lines @@
   final Uri location;
 }
 
 String _getHttpVersion() {
   var version = Platform.version;
   // Only include major and minor version numbers.
   int index = version.indexOf('.', version.indexOf('.') + 1);
   version = version.substring(0, index);
   return 'Dart/$version (dart:io)';
 }