the motivation is SwWrtShell::CalcAndSetScale

and the assert/crash triggered by

ooo58458-1.odt ooo84729-2.odt ooo75058-1.odt ooo123605-1.odt ooo102990-1.odt
fdo57249-1.odt fdo50880-1.odt fdo70223-5.odt ooo30052-2.odt ooo119280-1.odt
ooo79009-1.odt ooo58182-2.odt ooo59992-1.odt ooo123607-1.odt ooo89304-1.odt
ooo91578-5.odt ooo89303-1.odt ooo30052-1.odt fdo65664-3.odt ooo119941-1.odt
ooo55761-1.odt fdo57249-2.odt ooo83229-3.odt ooo84729-1.odt ooo102990-2.odt
ooo37749-1.sxw ooo38798-1.sxw ooo27909-1.sxw

getMapUnit activates the object which can cause chart object to load data from
the current document and appears to attempt to stop and resume pending layout
actions which can't be done if layout is underway, hence the assert from the
inner SwLayAction::SwLayAction triggered by the runstate while an SwLayAction::SwLayAction
is already active for counting the number of pdf output pages.

getMapUnit always returns the same result regardless of anything else and the
assumption is that we don't need to be in run state to setVisualSize on it

Change-Id: Ie75b159b140de223a56324b39699d703c3b40bb9