Stop working around issue 2644.

pkg/oauth2/lib/src/utils.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.
 
 library utils;
 
 import 'dart:async';
 import 'dart:isolate';
 
 import "package:crypto/crypto.dart";
 
 /// Adds additional query parameters to [url], overwriting the original
 /// parameters if a name conflict occurs.
 Uri addQueryParameters(Uri url, Map<String, String> parameters) {
   var queryMap = queryToMap(url.query);
-  mapAddAll(queryMap, parameters);
+  queryMap.addAll(parameters);
   return url.resolve("?${mapToQuery(queryMap)}");
 }
 
 /// Convert a URL query string (or `application/x-www-form-urlencoded` body)
 /// into a [Map] from parameter names to values.
 Map<String, String> queryToMap(String queryList) {
   var map = {};
   for (var pair in queryList.split("&")) {
     var split = split1(pair, "=");
     if (split.isEmpty) continue;
@@ skipping 13 matching lines @@
             ? null
             : Uri.encodeQueryComponent(value);
     pairs.add([key, value]);
   });
   return pairs.map((pair) {
     if (pair[1] == null) return pair[0];
     return "${pair[0]}=${pair[1]}";
   }).join("&");
 }
 
-/// Add all key/value pairs from [source] to [destination], overwriting any
-/// pre-existing values.
-void mapAddAll(Map destination, Map source) =>
-  source.forEach((key, value) => destination[key] = value);
-
 /// Decode a URL-encoded string. Unlike [Uri.decodeComponent], this includes
 /// replacing `+` with ` `.
 String urlDecode(String encoded) =>
   Uri.decodeComponent(encoded.replaceAll("+", " "));
 
 /// Like [String.split], but only splits on the first occurrence of the pattern.
 /// This will always return a list of two elements or fewer.
 List<String> split1(String toSplit, String pattern) {
   if (toSplit.isEmpty) return <String>[];
 
@@ skipping 45 matching lines @@
       throw new FormatException('Invalid WWW-Authenticate header: "$header"');
     }
 
     return new AuthenticateHeader(scheme, parameters);
   }
 }
 
 /// Returns a [Future] that asynchronously completes to `null`.
 Future get async => new Future.delayed(const Duration(milliseconds: 0),
                                        () => null);