code: function tabView_closeGroup(aSpec) {
      var spec = aSpec || {};
      var group = spec.group;
  
      if (!group) {
        throw new Error(arguments.callee.name + ": Group not specified.");
      }
  
      var button = this.getElement({
        type: "group_closeButton",
        value: group
      });
      this._controller.click(button);
  
      this.waitForGroupClosed({group: group});
    }
docs: Close the specified tab group
  
  @param {object} aSpec
  Information on which group to operate on
  Elements: group - Group