bug#19576: write-file writes the wrong buffer

[martin rudalics]

>> It might have interesting consequences.  Presumably, you expect that
>> this way we'll be finally able to run ‘window-size-change-functions’ if
>> and only if the size of windows really changed.  Correct?
>
> No, not really.  It's just a cleanup, IMO: instead of asking each
> caller of window_resize_apply to set that flag, set it in that
> function itself.

In addition it would do that then for grow_mini_window and
shrink_mini_window too but I suppose that's what you want.

> I didn't envision any changes in functionality due
> to this change.  What did I miss?

"All" window size changes must pass through window_resize_apply.  So we
could easily check there if any size really changes and set that flag
only in that case.  This way you would get your check whether
‘set-window-configuration’ did change the size of any window for free.

It's not a minor change since I probably would remove the check done by
‘window--resize-apply-p’, have window_resize_apply return a boolean
indicating that some size really changed and have ‘window-resize-apply’
pass that value back to its caller so we can avoid calling
‘window--pixel-to-total’ and ‘window-configuration-change-hook’ if
nothing changed.  And, as I mentioned earlier, the one case in
‘delete-other-windows’ would have to be treated specially.  But I think
it's worth if we care about ‘set-window-configuration’.

martin