Fix or mark "pub lish" build failures.

utils/pub/io.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.
 
 /**
  * Helper functionality to make working with IO easier.
  */
 library io;
 
 import 'dart:io';
@@ skipping 767 matching lines @@
   // exit codes). See issue 3657.
   var stream = new ListInputStream();
 
   if (baseDir == null) baseDir = currentWorkingDir;
   baseDir = getFullPath(baseDir);
   contents = contents.map((entry) {
     entry = getFullPath(entry);
     if (!isBeneath(entry, baseDir)) {
       throw 'Entry $entry is not inside $baseDir.';
     }
-    return new Path(entry).relativeTo(new Path(baseDir)).toNativePath();
+    return new Path.fromNative(entry).relativeTo(new Path.fromNative(baseDir))
+        .toNativePath();
   });
 
   if (Platform.operatingSystem != "windows") {
     var args = ["--create", "--gzip", "--directory", baseDir];
     args.addAll(contents.map(_getPath));
     // TODO(nweiz): It's possible that enough command-line arguments will make
     // the process choke, so at some point we should save the arguments to a
     // file and pass them in via --files-from for tar and -i@filename for 7zip.
     startProcess("tar", args).then((process) {
       pipeInputToInput(process.stdout, stream);
@@ skipping 93 matching lines @@
   return new Directory(entry);
 }
 
 /**
  * Gets a [Uri] for [uri], which can either already be one, or be a [String].
  */
 Uri _getUri(uri) {
   if (uri is Uri) return uri;
   return new Uri.fromString(uri);
 }