if (aAttrName == mFirst.mAttribute.mAtom) {
if (aAttrName == mFirst.mAttribute) {
nsHTMLMappedAttributes::UnsetAttribute(nsIAtom* aAttrName, PRInt32& aAttrCount){  if (! aAttrName) {    return NS_ERROR_NULL_POINTER;  }  if (aAttrName == mFirst.mAttribute.mAtom) {    if (mFirst.mNext) {      HTMLAttribute*  attr = mFirst.mNext;      mFirst = *attr;      mFirst.mNext = attr->mNext;      delete attr;    }    else {      mFirst.Reset();    }    mAttrCount--;  }  else {    if (HTMLAttribute::RemoveHTMLAttribute(aAttrName, &(mFirst.mNext))) {      mAttrCount--;    }  }  aAttrCount = mAttrCount;  return NS_OK;}