(enum save_restore_action): New.

(enum save_restore_action): New.
(save_restore_orig_size): Change parameter list.  Add
functionality to check for valid orig_top and orig_height members
in a window tree.
(grow_mini_window): Call save_restore_orig_size with new parameter
list.
(shrink_mini_window): Restore old window sizes only if old
size information is valid in all windows in a window tree.