getIcuFormattingPattern_(durationUnit) {
    const unitInfo = this.getIcuFormattingPatternsForUnit_(durationUnit);
    assertObject(unitInfo);
    return this.getIcuFormattingPatternForStyle_(unitInfo);
  }
From the data, return the information for the given unit and style.
@param {string} durationUnit
@return {string}
@private