one-liners for a few polymer-related libraries
one-liners for a few polymer-related libraries

R=jmesserly@google.com, mcampione@google.com

Review URL: https://codereview.chromium.org//23441054

git-svn-id: dae132d4ca6f88932ad8a9ec3641c81ad1592b72@27500 260f80e4-7a28-3924-810f-c04153c831b5

dart-lang/observe,dart-archive/observe