commit 4f27ff91
Author: Tor Lillqvist <tml@iki.fi>
Date:   Mon Jul 29 18:24:23 2013 +0300

    Avoid SolarMutex assertion in a dbgutil build when exiting Impress

put in a SolarMutex in that ImpTimedRefDev dtor for what sounds like
just this problem

commit 9f076691
Author: Armin Le Grand <Armin.Le.Grand@cib.de>
Date:   Fri Jul 1 14:40:00 2016 +0200

    tdf#50613 add support to load charts asynchronously

took it out again, to presumably move it into TextLayouterDevice
but we destroy this thing asyncronously outside of TextLayouterDevice
so lets put it back in again

Change-Id: If801a701701a3d87fce2f76bc22bb3184b46743a