I'm on Yosemite and just downloaded Lightroom CC. The plugins for the Extras to import from iPhoto or Aperture are greyed out. They are not selectable and not working.
Click on 'Plug-in Manager' in 'File' menu to open the manger dialog. Now select 'Aperture / iPhoto Importer' and click on 'Enable'. If you now go to the 'Plug-in Extra' menu option under 'File' menu the importer should be available.
Retrieving data ...