/**
     * Adds the contents of an existing media route selector to the builder.
     *
     * @param selector The media route selector whose contents are to be added.
     * @return The builder instance for chaining.
     */
    public Builder addSelector(MediaRouteSelector selector) {
      if (selector == null) {
        throw new IllegalArgumentException("selector must not be null");
      }

      addControlCategories(selector.getControlCategories());
      return this;
    }