get_preferred_width_for_height

Description:

public virtual void get_preferred_width_for_height (int height, out int minimum_width, out int natural_width)

Gets the accumulative preferred width for height for all rows which have been requested for the same said height with this context.

After reset is called and/or before ever requesting the size of a `GtkCellArea`, the returned values are -1.

this	a `GtkCellAreaContext`
height	a proposed height for allocation
minimum_width	location to store the minimum width
natural_width	location to store the natural width