Use "package:" imports for pub.

test/dart2js/reports_dart_parse_errors_test.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.
 
 import 'package:path/path.dart' as p;
+import 'package:pub/src/exit_codes.dart' as exit_codes;
 import 'package:scheduled_test/scheduled_test.dart';
 import 'package:scheduled_test/scheduled_stream.dart';
 
-import '../../lib/src/exit_codes.dart' as exit_codes;
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 
 main() {
   initConfig();
   integration("reports Dart parse errors", () {
     // Dart2js can take a long time to compile dart code, so we increase the
     // timeout to cope with that.
     currentSchedule.timeout *= 3;
 
@@ skipping 30 matching lines @@
     pub.shouldExit(exit_codes.DATA);
 
     // Doesn't output anything if an error occurred.
     d.dir(appPath, [
       d.dir('build', [
         d.nothing('web')
       ])
     ]).validate();
   });
 }