Support pub --with-prejudice.

sdk/lib/_internal/pub/bin/pub.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 'dart:async';
 import 'dart:io';
 
 import 'package:args/args.dart';
 import 'package:http/http.dart' as http;
 import 'package:path/path.dart' as path;
@@ skipping 14 matching lines @@
 
   try {
     options = PubCommand.pubArgParser.parse(arguments);
   } on FormatException catch (e) {
     log.error(e.message);
     log.error('Run "pub help" to see available options.');
     flushThenExit(exit_codes.USAGE);
     return;
   }
 
+  log.withPrejudice = options['with-prejudice'];
+
   if (options['version']) {
     log.message('Pub ${sdk.version}');
     return;
   }
 
   if (options['help']) {
     PubCommand.printGlobalUsage();
     return;
   }
 
@@ skipping 168 matching lines @@
     if (Platform.operatingSystem != 'windows') return null;
 
     return runProcess('ver', []).then((result) {
       if (result.stdout.join('\n').contains('XP')) {
         log.error('Sorry, but pub is not supported on Windows XP.');
         return flushThenExit(exit_codes.USAGE);
       }
     });
   });
 }