Unreviewed iOS build fix; move new symbols out of Mac-only exports.

* WebCore.exp.in:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@176501 268f45cc-cd09-0410-ab3c-d52691b4dbfc
Convert PassRefPtr return types to RefPtr.
<https://webkit.org/b/138995>

Reviewed by Anders Carlsson.

Convert an assortment of DOM and HTML related functions
to return RefPtr instead of PassRefPtr.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@176502 268f45cc-cd09-0410-ab3c-d52691b4dbfc