code: function addonsManager_getAddonLink(aSpec) {
      var spec = aSpec || { };
      var addon = spec.addon;
      var link = spec.link;
  
      if (!link)
        throw new Error(arguments.callee.name + ": Link not specified.");
  
      return this.getAddonChildElement({addon: addon, type: link + "Link"});
    }
docs: Returns the element of the specified add-ons link
  
  @param {object} aSpec
  Information on which add-on to operate on
  Elements: addon - Add-on element
  link  - Link
  List view (more, restart, undo)
  Detail view (findUpdates, restart, undo)
  
  @return Add-on link
  @type {ElemBase}