Remove deprecated Strings class.

Review URL: https://codereview.chromium.org//12295014

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@18686 260f80e4-7a28-3924-810f-c04153c831b5
3 files changed
tree: d2e4f2afe2ee3ccba10dc94074e0bc805c2c6af4
  1. lib/
  2. test/
  3. pubspec.yaml