nsIDocShellTreeOwner Interface

 Called when a content shell is added to the docshell tree.  This is
 _only_ called for "root" content shells (that is, ones whose parent is a
 chrome shell).

 @param aContentShell the shell being added.
 @param aPrimary whether the shell is primary.
 @param aTargetable whether the shell can be a target for named window
					targeting.
 @param aID the "id" of the shell.  What this actually means is
			undefined. Don't rely on this for anything.

void contentShellAdded(in nsIDocShellTreeItem aContentShell, in boolean aPrimary, in boolean aTargetable, in AString aID)

 Called when a content shell is removed from the docshell tree.  This is
 _only_ called for "root" content shells (that is, ones whose parent is a
 chrome shell).  Note that if aContentShell was never added,
 contentShellRemoved should just do nothing.

 @param aContentShell the shell being removed.

void contentShellRemoved(in nsIDocShellTreeItem aContentShell)