CSSStyleSheetImpl::AppendStyleSheet(nsICSSStyleSheet* aSheet)
CSSRuleProcessor::AppendStyleSheet(nsICSSStyleSheet* aStyleSheet)
CSSStyleSheetImpl::AppendStyleSheet(nsICSSStyleSheet* aSheet){  NS_PRECONDITION(nsnull != aSheet, "null arg");  if (NS_SUCCEEDED(WillDirty())) {    NS_ADDREF(aSheet);    CSSStyleSheetImpl* sheet = (CSSStyleSheetImpl*)aSheet;    if (! mFirstChild) {      mFirstChild = sheet;    }    else {      CSSStyleSheetImpl* child = mFirstChild;      while (child->mNext) {        child = child->mNext;      }      child->mNext = sheet;    }      // This is not reference counted. Our parent tells us when    // it's going away.    sheet->mParent = this;    DidDirty();  }  return NS_OK;}