It originally got introduced with b1da5a57
"CWS-TOOLING: integrate CWS alf01" but appears to have never been used.

Curiously, there were two commits to its code
(f565a4b3 "#i107087# TabWindowService must set
member pointer to zero on VCLEVENT_OBJECT_DYING. The window life time is
controlled by the docking window! Adding missing RemoveEventListener call" and
84c0ebe7 "#i107087# Remove event listener from
tab window on TabWindowService dtor") that mention
<https://bz.apache.org/ooo/show_bug.cgi?id=107087> "button merged in standard
toolbar + own UI caused office crash", but the description of which ("when i
merge a toolbar button in a standard toolbar and provide own UI (via the
toolkit) the office crashed sometimes") doesn't give a hint how this service
would have been used.  (Maybe it was intended to be used by extensions, but
never got documented neither in offapi's UNOIDL nor in
<https://wiki.openoffice.org/wiki/Documentation/DevGuide/OpenOffice.org_Developers_Guide>.)

Change-Id: I86746f73ee99ebe7f5afbc902204a9353e5ccb7b