Including the CoreFoundation header here and X11 headers
later will result in different definitions for Boolean. The
CoreFoundation include does not seem to be necessary here
and my mac build was successfull without it. I will remove
it for now. If the build bots disagree this will be replaced
by a #if PLATFORM(CF).

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@43634 268f45cc-cd09-0410-ab3c-d52691b4dbfc