mObservers.RemoveObject(aObserver);
if (mObservers) { mObservers->RemoveElement(aObserver); }
nsBookmarksService::RemoveObserver(nsIRDFObserver* aObserver){    if (! aObserver)        return NS_ERROR_NULL_POINTER;    mObservers.RemoveObject(aObserver);    return NS_OK;}