- Reverting mirror changes.
- Reverting mirror changes.

Review URL: https://codereview.chromium.org//62373008

git-svn-id: dae132d4ca6f88932ad8a9ec3641c81ad1592b72@30029 260f80e4-7a28-3924-810f-c04153c831b5

dart-lang/observe,dart-archive/observe