Moving logic for writing source maps from SourceMapBuilder into the Mapping class.

R=sigmund@google.com

Review URL: https://codereview.chromium.org//372153002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart/pkg/source_maps@38073 260f80e4-7a28-3924-810f-c04153c831b5
3 files changed
tree: 928ce5a51f6b0a3a765a51fdc3f7dc3724551f8a
  1. pkgs/