nsIOfflineCacheUpdateObserver Interface

 The manifest is being checked for updates

 @param aUpdate
        The nsIOfflineCacheUpdate being processed.

void checking(in nsIOfflineCacheUpdate aUpdate)

 Starting to download resources

 @param aUpdate
        The nsIOfflineCacheUpdate being processed.

void downloading(in nsIOfflineCacheUpdate aUpdate)

 There was an error updating the cache.

 @param aUpdate
        The nsIOfflineCacheUpdate being processed.

void error(in nsIOfflineCacheUpdate aUpdate)

 An item has finished loading.

 @param aUpdate
        The nsIOfflineCacheUpdate being processed.
 @param aItem
         load status for the item that completed.

void itemCompleted(in nsIOfflineCacheUpdate aUpdate, in nsIDOMLoadStatus aItem)

 An item has started downloading.

 @param aUpdate
        The nsIOfflineCacheUpdate being processed.
 @param aItem
        load status for the item that is being downloaded.

void itemStarted(in nsIOfflineCacheUpdate aUpdate, in nsIDOMLoadStatus aItem)

 No update was necessary.

 @param aUpdate
        The nsIOfflineCacheUpdate being processed.

void noUpdate(in nsIOfflineCacheUpdate aUpdate)

 The cache group is now obsolete.

 @param aUpdate
        The nsIOfflineCacheUpdate being processed.

void obsolete(in nsIOfflineCacheUpdate aUpdate)