String to OUString and SDIs

[Matteo Casalin]

Hi all,
     I'm currently working in String to OUString conversion. Randomly, I 
started converting include/svl/poolitem.hxx (just removing an unused 
#include <tools/string.hxx>), and this started a long sequence of files 
to be fixed. In these, I found that some classes are referred by SDI 
files [1].
Before putting too much effort in this patch, I wonder if anybody has 
any advice on whether this conversion will break something (even for 
compatibility) or not.
I would perform a "make clean; make dev-install" before submission to 
gerrit, just to verify that no major issue exist, but if it's already 
known to break something I can focus on other areas.

Thanks in advance
Cheers
Matteo

[1] e.g. SfxStringListItem which is in
* /core/svx/sdi/svxitems.sdi:
      394 item String SfxStringListItem;
* /core/svx/sdi/svx.sdi:
      940 SfxStringListItem GetRedoStrings SID_GETREDOSTRINGS
     4967 SfxStringListItem GetUndoStrings SID_GETUNDOSTRINGS
    15338 SfxStringListItem FontNameStringList SID_FONTNAMELIST
    15379 SlotType = SfxStringListItem