Reschedule callbacks execution on failure.
Reschedule callbacks execution on failure.

Otherwise if there is any remaining callback,
Timer.run will never schedule next batch to run
as callbacks list is longer than 1.

R=ajohnsen@google.com, floitsch@google.com
BUG=9857

Review URL: https://codereview.chromium.org//13911005

git-svn-id: c93d8a2297af3b929165606efe145742a534bc71@21352 260f80e4-7a28-3924-810f-c04153c831b5

dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk