return NS_ERROR_ILLEGAL_VALUE; }
  nsresult  SetCounterIncrementAt(PRUint32 aIndex, const nsString& aCounter, PRInt32 aIncrement) {    if (aIndex < mIncrementCount) {      mIncrements[aIndex].mCounter = aCounter;      mIncrements[aIndex].mValue = aIncrement;      return NS_OK;    }    return NS_ERROR_ILLEGAL_VALUE;  }