function getContrastColor(contrastType) {
      switch (contrastType) {
        default:
        case 'strongLight':
          return STRONG_LIGHT_CONTRAST_COLOR;
        case 'light':
          return LIGHT_CONTRAST_COLOR;
        case 'dark':
          return DARK_CONTRAST_COLOR;
      }
    }
@param {'dark'|'light'|'strongLight'} contrastType
@return {[number, number, number]} [red, green, blue] array