Fix barback test.
Fix barback test.

R=nweiz@google.com

Review URL: https://codereview.chromium.org//54723004

git-svn-id: c93d8a2297af3b929165606efe145742a534bc71@29693 260f80e4-7a28-3924-810f-c04153c831b5

dart-lang/barback,dart-archive/barback,dart-archive/barback,Aetet/barback,dart-lang/barback,Aetet/barback