nsresult rv; if (aSource == kNC_HistoryRoot && aProperty == kNC_child) {  nsCOMPtr<nsIRDFResource> resource = do_QueryInterface(aTarget, &rv);  if (NS_FAILED(rv)) return NS_RDF_ASSERTION_REJECTED;  nsXPIDLCString targetUrl; rv = resource->GetValueConst(getter_Shares(targetUrl)); if (NS_FAILED(rv)) return NS_RDF_ASSERTION_REJECTED;   rv = RemovePage(targetUrl); if (NS_FAILED(rv)) return NS_RDF_ASSERTION_REJECTED;  return NS_OK; }
nsGlobalHistory::Unassert(nsIRDFResource* aSource,                          nsIRDFResource* aProperty,                          nsIRDFNode* aTarget){  // History cannot be modified  return NS_RDF_ASSERTION_REJECTED;}