nsINavHistoryObserver in Firefox 3.6a1pre

 This page and all of its visits are about to be deleted.  Note: the page
 may not necessarily have actually existed for this function to be called.

 @param aURI
        The URI being deleted.

 Notifies you that a bunch of things are about to change, don't do any
 heavy-duty processing until onEndUpdateBatch is called.

 Notification that all of history is being deleted.

 This page and all of its visits are being deleted. Note: the page may not
 necessarily have actually existed for this function to be called.

 Delete notifications are only 99.99% accurate. Batch delete operations
 must be done in two steps, so first come notifications, then a bulk
 delete. If there is some error in the middle (for example, out of memory)
 then you'll get a notification and it won't get deleted. There's no easy
 way around this.

 Notifies you that we are done doing a bunch of things and you should go
 ahead and update UI, etc.

 Called when a history entry expires. You will receive notifications that
 a specific visit has expired with the time of that visit. When the last
 visit for a history entry expires, the history entry itself is deleted
 and aWholeEntry is set. (If your observer only cares about URLs and not
 specific visits, it needs only to listen for aWholeEntry notifications).

 It is possible for a history entry to be deleted that has no visits if
 something is out of sync or after a bookmark is deleted that has no
 visits (thus freeing the history entry). In these cases, aVisitTime will
 be 0.

 Called whenever either the "real" title or the custom title of the page
 changed. BOTH TITLES ARE ALWAYS INCLUDED in this notification, even though
 only one will change at a time. Often, consumers will want to display the
 user title if it is available, and fall back to the page title (the one
 specified in the <title> tag of the page).

 Note that there is a difference between an empty title and a NULL title.
 An empty string means that somebody specifically set the title to be
 nothing. NULL means nobody set it. From C++: use IsVoid() and SetIsVoid()
 to see whether an empty string is "null" or not (it will always be an
 empty string in either case).

 Called when a resource is visited. This is called the first time a
 resource (page, image, etc.) is seen as well as every subsequent time.

 Normally, transition types of TRANSITION_EMBED (corresponding to images in
 a page, for example) are not displayed in history results (unless
 includeHidden is set). Many observers can ignore _EMBED notifications
 (which will comprise the majority of visit notifications) to save work.

 @param aVisitID        ID of the visit that was just created.
 @param aTime           Time of the visit
 @param aSessionID      The ID of one connected sequence of visits.
 @param aReferringID    The ID of the visit the user came from. 0 if empty.
 @param aTransitionType One of nsINavHistory.TRANSITION_*
 @param aAdded          Incremented by query nodes when the visited uri
                        belongs to them. If no such query exists, the 
                        history result creates a new query node dynamically.
                        It is used in places views only and can be ignored.