SetURLListener(nsnull); SetContainer(nsnull); SetObserver(nsnull);  if (nsnull != mDocLoader) { mDocLoader->SetContainer(nsnull); }  NS_IF_RELEASE(mContentViewer);   DestroyChildren(); return rv;
return NS_OK;
nsWebShell::Destroy(){  nsresult rv = NS_OK;  // Stop any URLs that are currently being loaded...  Stop();  SetURLListener(nsnull);  SetContainer(nsnull);  SetObserver(nsnull);  if (nsnull != mDocLoader) {    mDocLoader->SetContainer(nsnull);  }  NS_IF_RELEASE(mContentViewer);  // Destroy our child web shells and release references to them  DestroyChildren();  return rv;}