_handleChevronIncrease() {
    if (this._currentShownStars == SDK.RankFactory.starsNeededToAdvanceRank(this._currentShownRank)) {
      // Show a rank up then a chevron gain
      return this._animateGainingRank().then(() => this._animateGainingChevron());
    } if (this._currentShownStars + 1 == SDK.RankFactory.starsNeededToAdvanceRank(this._currentShownRank)) {
      // Show chevron gain then a rank up
      return this._animateGainingChevron().then(() => this._animateGainingRank());
    }
    return this._animateGainingChevron();
  }
Iterates rank stars up by one and calls necessary animations
@private