[Mac] Add DOMWindowConstructors.idl to Xcode project file
        https://bugs.webkit.org/show_bug.cgi?id=116351

        Reviewed by Anders Carlsson.

        * WebCore.xcodeproj/project.pbxproj: Added the file, so that Xcode includes it
        in searches.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@150300 268f45cc-cd09-0410-ab3c-d52691b4dbfc