Move a number of packages and some of pub over to using source_span.
Move a number of packages and some of pub over to using source_span.

R=efortuna@google.com, rnystrom@google.com, sigmund@google.com
BUG=19930

Review URL: https://codereview.chromium.org//401753002

git-svn-id: 0aa7e0b98478d6ef7145d04e8154f8ab2209deba@38526 260f80e4-7a28-3924-810f-c04153c831b5

dart-archive/polymer-dart,dam0vm3nt/polymer-dart,jakemac53/polymer-dart,meflyup/polymer-dart,meflyup/polymer-dart,jakemac53/polymer-dart,dart-archive/polymer-dart,dam0vm3nt/polymer-dart,ronlobo/polymer-dart,ronlobo/polymer-dart