updateScrollValues(x, y) {
        this._scrollManager.updateScrollValues(x, y);
    }
Updates the scroll manager X and Y scroll values as well as last X and Y deltas
     Internally called by the scroll handler if at least one plane is watching the scroll
     Could be called externally as well if the user wants to handle the scroll by himself

     params:
     @x (float): scroll value along X axis
     @y (float): scroll value along Y axis
*