rippleShouldTrigger(isTouch) {
        const shouldStart = isTouch ? true : !this.touchCache;
        this.touchCache = isTouch;
        return shouldStart;
      }
Determine if a ripple should start depending if its a touch event. For mobile both
touchStart and mouseDown are launched so in case is touch we should always trigger
but if its not we should check if a touch was already triggered to decide.

@param {Boolean} isTouch True in case a touch event triggered the ripple false otherwise.
@return {Boolean} True in case the ripple should trigger or false if it shouldn't.