218e366f89
This adds support for file locking in dart:io. BUG=http://dartbug.com/17045 R=kustermann@google.com, lrn@google.com Review URL: https://codereview.chromium.org//833623004 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@42733 260f80e4-7a28-3924-810f-c04153c831b5