Added kUnboundedSize (~0) to specify unlimited capacity instead of using 0.
Trimming a quarantine with max size 0 should flush it.
BUG=
R=chrisha@chromium.org

Review URL: https://codereview.appspot.com/139830043

git-svn-id: http://sawbuck.googlecode.com/svn/trunk@2287 15e8cca8-e42c-11de-a347-f34a4f72eb7d