Do *not* make file handles inheritable on Windows.

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 637 matching lines @@
   var pathTo7zip = '../../third_party/7zip/7za.exe';
   var command = scriptDir.append(pathTo7zip).canonicalize().toNativePath();
 
   var tempDir;
 
   return createTempDir().chain((temp) {
     // Write the archive to a temp file.
     tempDir = temp;
     return createFileFromStream(stream, join(tempDir, 'data.tar.gz'));
   }).chain((_) {
-    // TODO(rnystrom): Hack. We get intermittent "file already in use" errors.
-    // It looks like the 7zip process is starting up before the file has
-    // finished being written. So we'll just sleep for a couple of seconds
-    // here. :(
-    return sleep(2000);
-  }).chain((_) {
     // 7zip can't unarchive from gzip -> tar -> destination all in one step
     // first we un-gzip it to a tar file.
     // Note: Setting the working directory instead of passing in a full file
     // path because 7zip says "A full path is not allowed here."
     return runProcess(command, ['e', 'data.tar.gz'], workingDir: tempDir);
   }).chain((result) {
     if (result.exitCode != 0) {
       throw 'Could not un-gzip (exit code ${result.exitCode}). Error:\n'
           '${Strings.join(result.stdout, "\n")}\n'
           '${Strings.join(result.stderr, "\n")}';
@@ skipping 80 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);
 }