Function: window-resize-apply

Apply requested size values for window-tree of FRAME.
Optional argument HORIZONTAL omitted or nil means apply requested height
values. HORIZONTAL non-nil means apply requested width values.

This function checks whether the requested values sum up to a valid
window layout, recursively assigns the new sizes of all child windows
and calculates and assigns the new start positions of these windows.

Note: This function does not check any of `window-fixed-size-p',
`window-min-height' or `window-min-width'. All these checks have to
be applied on the Elisp level. (fn FRAME &optional HORIZONTAL)