Stop working around issue 7790 in pub.

utils/pub/oauth2.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 oauth2;
 
 import 'dart:async';
 import 'dart:io';
 import 'dart:uri';
 
@@ skipping 51 matching lines @@
 
 /// Asynchronously passes an OAuth2 [Client] to [fn], and closes the client when
 /// the [Future] returned by [fn] completes.
 ///
 /// This takes care of loading and saving the client's credentials, as well as
 /// prompting the user for their authorization. It will also re-authorize and
 /// re-run [fn] if a recoverable authorization error is detected.
 Future withClient(SystemCache cache, Future fn(Client client)) {
   return _getClient(cache).then((client) {
     var completer = new Completer();
-    return asyncWhenComplete(fn(client), () {
+    return fn(client).whenComplete(() {
       client.close();
       // Be sure to save the credentials even when an error happens.
       return _saveCredentials(cache, client.credentials);
     });
   }).catchError((asyncError) {
     var e = getRealError(asyncError);
     if (e is ExpirationException) {
       log.error("Pub's authorization to upload packages has expired and "
           "can't be automatically refreshed.");
       return withClient(cache, fn);
@@ skipping 116 matching lines @@
       'Pub needs your authorization to upload packages on your behalf.\n'
       'In a web browser, go to $authUrl\n'
       'Then click "Allow access".\n\n'
       'Waiting for your authorization...');
 
   return completer.future.then((client) {
     log.message('Successfully authorized.\n');
     return client;
   });
 }