Fix lingering references to the old Span in yaml.

R=rnystrom@google.com
BUG=

Review URL: https://codereview.chromium.org//413403002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart/pkg/yaml@38656 260f80e4-7a28-3924-810f-c04153c831b5
5 files changed
tree: 30657c81e28e9e67b56b38dcc91d133da1cd7930
  1. pkgs/