[PATCH v6 2/7] comctl32/listbox: Use a helper to expand the item array

[Nikolay Sivov]

I did some testing on Windows, and LB_INITSTORAGE is not supposed to 
work the way it's implemented right now, before or after your patch.

Summary of what I found:

- LB_INITSTORAGE should return current capacity, 'items_size' in our 
case, not LB_OKAY;
- it's not additive, and calling it for 0 count does not increase 
returned value, policy is items_size = max(items_size, wParam + 10);
- it never shrinks as far as I can tell from return value, items_size is 
reset to 0 only on LB_RESETCONTENT, same for LB_DELETESTRING;
- array grows by 32 items, not 16;
- there is no alignment when growing on insert, so LB_RESETCONTENT -> 
LB_INITSTORAGE(1) -> LB_ADDSTRING twice -> items_size is 33.

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