Big merge from experimental to bleeding edge.

pkg/oauth2/lib/src/client.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 client;
 
+import 'dart:async';
 import 'dart:uri';
 
 import '../../../http/lib/http.dart' as http;
 
 import 'authorization_exception.dart';
 import 'credentials.dart';
 import 'expiration_exception.dart';
 import 'utils.dart';
 
 // TODO(nweiz): Add an onCredentialsRefreshed event once we have some event
@@ skipping 57 matching lines @@
       this.identifier,
       this.secret,
       this._credentials,
       {http.Client httpClient})
     : _httpClient = httpClient == null ? new http.Client() : httpClient;
 
   /// Sends an HTTP request with OAuth2 authorization credentials attached. This
   /// will also automatically refresh this client's [Credentials] before sending
   /// the request if necessary.
   Future<http.StreamedResponse> send(http.BaseRequest request) {
-    return async.chain((_) {
+    return async.then((_) {
       if (!credentials.isExpired) return new Future.immediate(null);
       if (!credentials.canRefresh) throw new ExpirationException(credentials);
       return refreshCredentials();
-    }).chain((_) {
+    }).then((_) {
       request.headers['authorization'] = "Bearer ${credentials.accessToken}";
       return _httpClient.send(request);
-    }).transform((response) {
+    }).then((response) {
       if (response.statusCode != 401 ||
           !response.headers.containsKey('www-authenticate')) {
         return response;
       }
 
       var authenticate;
       try {
         authenticate = new AuthenticateHeader.parse(
             response.headers['www-authenticate']);
       } on FormatException catch (e) {
@@ skipping 13 matching lines @@
   /// Explicitly refreshes this client's credentials. Returns this client.
   ///
   /// This will throw a [StateError] if the [Credentials] can't be refreshed, an
   /// [AuthorizationException] if refreshing the credentials fails, or a
   /// [FormatError] if the authorization server returns invalid responses.
   ///
   /// You may request different scopes than the default by passing in
   /// [newScopes]. These must be a subset of the scopes in the
   /// [Credentials.scopes] field of [Client.credentials].
   Future<Client> refreshCredentials([List<String> newScopes]) {
-    return async.chain((_) {
+    return async.then((_) {
       if (!credentials.canRefresh) {
         var prefix = "OAuth credentials";
         if (credentials.isExpired) prefix = "$prefix have expired and";
         throw new StateError("$prefix can't be refreshed.");
       }
 
       return credentials.refresh(identifier, secret,
           newScopes: newScopes, httpClient: _httpClient);
-    }).transform((credentials) {
+    }).then((credentials) {
       _credentials = credentials;
       return this;
     });
   }
 
   /// Closes this client and its underlying HTTP client.
   void close() {
     if (_httpClient != null) _httpClient.close();
     _httpClient = null;
   }
 }