// TODO(kevinb): split the && into two if's and move crossOverUp so it's
      // only called when there's no child.
      if ((minChildIndex > 0) && (ordering.compare(elementData(minChildIndex), x) < 0)) {
        queue[index] = elementData(minChildIndex);
        queue[minChildIndex] = x;
        return minChildIndex;
      }
      return crossOverUp(index, x);
    }

    /**