valueToAngle_(value) {
    const valuePct = this.valueToRangePosition_(value);
    return this.valuePositionToAngle_(valuePct);
  }
Convert a value to an angle based on the value range and angle span
@param {number} value The value.
@return {number} The angle where this value is located on the round
    axis, based on the range and angle span.
@private