/* Returns total width of all date cells. */
  private int getDatesWidth() {
    if (weekGrid.width == -1) {
      // Undefined width. Needs to be calculated by the known cell
      // widths.
      int count = weekGrid.content.getWidgetCount() - 1;
      return count * getDateCellWidth();
    }

    return weekGrid.getInternalWidth();
  }