In preparation of adding a button to the toolbar.

Change-Id: Icd97f828def1aacbb92297e8e74bdd2310c4d0f8
Reviewed-on: https://gerrit.libreoffice.org/45731Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Eike Rathke <erack@redhat.com>