It was added as a stub to LayoutTestControllerWin.cpp in http://trac.webkit.org/changeset/97407 and never fleshed out.
In some ways, it would have been better to have omitted the stub on Windows, so it would be more obvious which tests use it and need to be Skipped on Windows
Added tests to the Windows Skipped list in http://trac.webkit.org/changeset/119039
Created attachment 255608 [details]
I'll unskip the tests Jessie skipped back in 2012 once the builders catch up and I can identify any minor differences due to font and other variations with Windows.
Committed r185982: <http://trac.webkit.org/changeset/185982>
The following tests now work properly: