The SdrObject got a new method SetContextWritingMode, taking a value
from the css.text.WritingMode2 constants group, and defining the
writing mode of the object's context. The definition of "context"
depends on the application the object lives in, and properties of the
object itself (such as its anchor type). For instance, in spreadsheets
an object's context is always the complete sheet, in text documents,
the context is defined by where the object is anchored to.
The ContextWritingMode of an SdrObject is only evaluated for instances
which itself support different writing modes (which currently is the
case for form controls only). Here, it needs to be a *concrete* value
from the css.text.WritingMode2 group (in particular,
WritingMode2.CONTEXT itself is invalid), telling the "effective"
writing mode of the object's context.
It's up to the application which uses SdrObjects to update the
ContextWritingMode whenever necessary. All changes for this have been
done in CWS rtlcontrols, in both Calc and Writer.