Remove unused imports in pub.

sdk/lib/_internal/pub/test/oauth2/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 oauth2.utils;
 
 import 'dart:io';
 import 'dart:json' as json;
 
 import 'package:http/http.dart' as http;
 import 'package:scheduled_test/scheduled_process.dart';
 import 'package:scheduled_test/scheduled_test.dart';
 import 'package:scheduled_test/scheduled_server.dart';
 
 import '../../lib/src/io.dart';
 import '../../lib/src/utils.dart';
-import '../test_pub.dart';
 
 void authorizePub(ScheduledProcess pub, ScheduledServer server,
     [String accessToken="access token"]) {
   expect(pub.nextLine(), completion(equals('Pub needs your authorization to '
       'upload packages on your behalf.')));
 
   expect(pub.nextLine().then((line) {
     var match = new RegExp(r'[?&]redirect_uri=([0-9a-zA-Z%+-]+)[$&]')
         .firstMatch(line);
     expect(match, isNotNull);
@@ skipping 20 matching lines @@
           new ContentType("application", "json");
       request.response.write(json.stringify({
         "access_token": accessToken,
         "token_type": "bearer"
       }));
       request.response.close();
     });
   });
 }