nsINavHistoryResultViewer Interface

 Called after a container node went from opened to closed. This will be
 called for the topmost container that is closing, and implies that any
 child containers have closed as well.

void containerClosed(in nsINavHistoryContainerResultNode item)

 Called after a container node went from closed to opened.

void containerOpened(in nsINavHistoryContainerResultNode item)

 Called when something significant is changing that requires everything
 to be recomputed. For example, changing sorting can affect every row.

void invalidateAll()

 Called when something significant has happened within the container. The
 contents of the container should be re-built.

void invalidateContainer(in nsINavHistoryContainerResultNode item)

 Called when an item has been changed and should be repainted. This only
 refers to the specific item. If it is a container, getting this message
 does not imply anything happened to the children. You'll get separate
 messages for those. Also, this may be called for container nodes at times
 when the result thinks it's possible that a twisty mey need to bw redrawn.

void itemChanged(in nsINavHistoryResultNode item)

 Called when 'aItem' is inserted into 'aParent' at index 'aNewIndex'.
 The item previously at index (if any) and everything below it will have
 been shifted down by one. The item may be a container or a leaf.

void itemInserted(in nsINavHistoryContainerResultNode aParent, in nsINavHistoryResultNode aItem, in unsigned long aNewIndex)

 Called whan 'aItem' is moved from 'aOldParent' at 'aOldIndex' to
 aNewParent at aNewIndex. The item may be a container or a leaf.

 XXX: at the moment, this method is called only when an item is moved
 within the same container. When an item is moved between containers,
 a new node is created for the item, and the itemRemoved/itemAdded methods
 are used.

void itemMoved(in nsINavHistoryResultNode aItem, in nsINavHistoryContainerResultNode aOldParent, in unsigned long aOldIndex, in nsINavHistoryContainerResultNode aNewParent, in unsigned long aNewIndex)

 Called whan 'aItem' is removed from 'aParent' at 'aOldIndex'. The item
 may be a container or a leaf. This function will be called after the item
 has been removed from its parent list, but before anything else (including
 NULLing out the item's parent) has happened.

void itemRemoved(in nsINavHistoryContainerResultNode aParent, in nsINavHistoryResultNode aItem, in unsigned long aOldIndex)

 Called when an item is being replaced with another item at the exact
 same position.

void itemReplaced(in nsINavHistoryContainerResultNode parent, in nsINavHistoryResultNode oldItem, in nsINavHistoryResultNode newItem, in unsigned long index)

 This is called to indicate to the UI that the sort has changed to the
 given mode. For trees, for example, this would update the column headers
 to reflect the sorting. For many other types of views, this won't be
 applicable.

 @param sortingMode  One of nsINavHistoryQueryOptions.SORT_BY_* that
                     indicates the new sorting mode.

 This only is expected to update the sorting UI. invalidateAll() will also
 get called if the sorting changes to update everything.

void sortingChanged(in unsigned short sortingMode)