Fixes in sourcemaps discovered in csslib

R=dgrove@google.com

Review URL: https://codereview.chromium.org//18749005

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart/pkg/source_maps@24881 260f80e4-7a28-3924-810f-c04153c831b5
2 files changed
tree: 86971de83814cc94f53efaee2f0d0fa14b3f7574
  1. pkgs/