aWebShell->GetContentViewer(cv);
aWebShell->GetContentViewer(&cv);
GetPresShellFor(nsIWebShell* aWebShell){  nsIPresShell* shell = nsnull;  if (nsnull != aWebShell) {    nsIContentViewer* cv = nsnull;    aWebShell->GetContentViewer(cv);    if (nsnull != cv) {      nsIDocumentViewer* docv = nsnull;      cv->QueryInterface(kIDocumentViewerIID, (void**) &docv);      if (nsnull != docv) {        nsIPresContext* cx;        docv->GetPresContext(cx);	      if (nsnull != cx) {	        shell = cx->GetShell();	        NS_RELEASE(cx);	      }        NS_RELEASE(docv);      }      NS_RELEASE(cv);    }  }  return shell;}