An interface describing a global application service that maintains a list
of updates previously performed as well as the current active update.
Gets the update at the specified index
| index | The index within the updates array |
| The nsIUpdate object at the specified index |
Saves all updates to disk.
Refresh the update status based on the information in update.status.
Gets the total number of updates in the history list.
The active (current) update. The active update is not in the history list.