from

    commit 8d4a306e
    Author: Noel Grandin <noel.grandin@collabora.co.uk>
    Date:   Tue Nov 15 11:26:59 2016 +0200
    loplugin:unusedfields

and

    commit c79b7fd8
    Author: Noel Grandin <noel@peralex.com>
    Date: 2015-11-20 10:41:00 (GMT)
    loplugin:unusedfields in chart2

Change-Id: I6b61aa9c6abb1d51e96d5eb6c623d86fd6fd5b82