nsresult rv = NS_OK;
nsresult nsPrefWindowFactory::CreateInstance(	nsISupports* /* aOuter */,	const nsIID &aIID,	void** aResult)  //----------------------------------------------------------------------------------------{  	if (aResult == nsnull)  		return NS_ERROR_NULL_POINTER;  	nsresult rv = NS_OK;	*aResult = nsnull;    //	if (!mClassID.Equals(nsPrefWindow::GetCID())) //		return NS_NOINTERFACE;	*aResult = nsPrefWindow::Get();	return NS_OK;}  // nsPrefWindowFactory::CreateInstanc