function si(
    cssClass, url = undefined, width = undefined, height = undefined,
    xOffset = undefined, yOffset = undefined, animated = undefined) {
  return new SpriteInfo(
      cssClass, url, width, height, xOffset, yOffset, animated);
}
Creates a SpriteInfo object with the specified properties. If the image is
sprited via CSS, then only the first parameter needs a value. If the image
is sprited via metadata, then the first parameter should be left null.
@param {?string} cssClass CSS class to properly display the sprited image.
@param {string=} url Url of the sprite image.
@param {number=} width Width of the image being sprited.
@param {number=} height Height of the image being sprited.
@param {number=} xOffset Positive x offset of the image being sprited within
    the sprite.
@param {number=} yOffset Positive y offset of the image being sprited within
    the sprite.
@param {boolean=} animated Whether the sprite info is for an animated emoji.