if (nsnull != mContentStyleRule) {
if (aDocument != mDocument && mContentStyleRule) {
nsHTMLBodyElement::SetDocument(nsIDocument* aDocument, PRBool aDeep,                               PRBool aCompileEventHandlers){  if (nsnull != mContentStyleRule) {    mContentStyleRule->mPart = nsnull;    mContentStyleRule->mSheet = nsnull;    // destroy old style rule since the sheet will probably change    NS_RELEASE(mContentStyleRule);  }  return nsGenericHTMLContainerElement::SetDocument(aDocument, aDeep,                                                    aCompileEventHandlers);}