Fix source spans for scalars.

Closes dart-lang/yaml#13

R=pquitslund@google.com, rnystrom@google.com

Review URL: https://codereview.chromium.org//1329183002 .
4 files changed
tree: d1f7ac210ee1b39d96b58410b0823c9a57961d7c
  1. pkgs/