Add a package for authenticating via OAuth2.

Review URL: https://codereview.chromium.org//11420025

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@15115 260f80e4-7a28-3924-810f-c04153c831b5
13 files changed
tree: 3b40cb308049f6fca8fa77199c6e002492dc6952
  1. lib/
  2. test/