code: function materialEase(currentTime, startValue, changeInValue, duration) {
      var /** @type {?} */ time = currentTime / duration;
      var /** @type {?} */ timeCubed = Math.pow(time, 3);
      var /** @type {?} */ timeQuad = Math.pow(time, 4);
      var /** @type {?} */ timeQuint = Math.pow(time, 5);
      return startValue + changeInValue * ((6 * timeQuint) + (-15 * timeQuad) + (10 * timeCubed));
  }
docs: Easing function to match material design indeterminate animation.
  @param {?} currentTime
  @param {?} startValue
  @param {?} changeInValue
  @param {?} duration
  @return {?}