Merge the dart:uri library into dart:core and update the Uri class

pkg/http/lib/src/multipart_request.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.
 
 library multipart_request;
 
 import 'dart:async';
 import 'dart:io';
 import 'dart:math';
-import 'dart:uri';
 import 'dart:utf';
 
 import 'base_request.dart';
 import 'byte_stream.dart';
 import 'multipart_file.dart';
 import 'utils.dart';
 
 /// A `multipart/form-data` request. Such a request has both string [fields],
 /// which function as normal form fields, and (potentially streamed) binary
 /// [files].
@@ skipping 110 matching lines @@
     104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118,
     119, 120, 121, 122
   ];
 
   /// Returns the header string for a field. The return value is guaranteed to
   /// contain only ASCII characters.
   String _headerForField(String name, String value) {
     // http://tools.ietf.org/html/rfc2388 mandates some complex encodings for
     // field names and file names, but in practice user agents seem to just
     // URL-encode them so we do the same.
-    var header = 'content-disposition: form-data; name="${encodeUri(name)}"';
+    var header =
+        'content-disposition: form-data; name="${Uri.encodeFull(name)}"';
     if (!isPlainAscii(value)) {
       header = '$header\r\ncontent-type: text/plain; charset=utf-8';
     }
     return '$header\r\n\r\n';
   }
 
   /// Returns the header string for a file. The return value is guaranteed to
   /// contain only ASCII characters.
   String _headerForFile(MultipartFile file) {
     var header = 'content-type: ${file.contentType}\r\n'
-      'content-disposition: form-data; name="${encodeUri(file.field)}"';
+      'content-disposition: form-data; name="${Uri.encodeFull(file.field)}"';
 
     if (file.filename != null) {
-      header = '$header; filename="${encodeUri(file.filename)}"';
+      header = '$header; filename="${Uri.encodeFull(file.filename)}"';
     }
     return '$header\r\n\r\n';
   }
 
   /// Returns a randomly-generated multipart boundary string of the given
   /// [length].
   String _boundaryString(int length) {
     var prefix = "dart-http-boundary-";
     var list = new List<int>(length - prefix.length);
     for (var i = 0; i < list.length; i++) {
       list[i] = _BOUNDARY_CHARACTERS[
           _random.nextInt(_BOUNDARY_CHARACTERS.length)];
     }
     return "$prefix${new String.fromCharCodes(list)}";
   }
 }