Get rid of join() and encapsulate File and Directory in io.dart.

utils/pub/command_lish.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 command_lish;
 
 import 'dart:async';
 import 'dart:io';
 import 'dart:json';
 import 'dart:uri';
@@ skipping 118 matching lines @@
   /// archives.
   final _BLACKLISTED_DIRS = const ['packages'];
 
   /// Returns a list of files that should be included in the published package.
   /// If this is a Git repository, this will respect .gitignore; otherwise, it
   /// will return all non-hidden files.
   Future<List<String>> get _filesToPublish {
     var rootDir = entrypoint.root.dir;
 
     return git.isInstalled.then((gitInstalled) {
-      if (dirExists(join(rootDir, '.git')) && gitInstalled) {
+      if (dirExists(path.join(rootDir, '.git')) && gitInstalled) {
         // List all files that aren't gitignored, including those not checked
         // in to Git.
         return git.run(["ls-files", "--cached", "--others",
                         "--exclude-standard"]);
       }
 
       return listDir(rootDir, recursive: true).then((entries) {
         return entries
             .where(fileExists) // Skip directories.
             .map((entry) => path.relative(entry, from: rootDir));
@@ skipping 47 matching lines @@
       return confirm(message).then((confirmed) {
         if (!confirmed) {
           log.error("Package upload canceled.");
           return false;
         }
         return true;
       });
     });
   }
 }