Stop exporting Widget::frameRectsChanged()
https://bugs.webkit.org/show_bug.cgi?id=119196

Reviewed by Darin Adler.

The definition is inlined in a private header, so there's no need to
export a symbol to link against. On the Mac, since we compile with
-fvisibility-inlines-hidden, removing the symbol from the export file
silences an ld warning about exporting a hidden symbol.

* WebCore.exp.in: Removed __ZN7WebCore6Widget17frameRectsChangedEv.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153413 268f45cc-cd09-0410-ab3c-d52691b4dbfc