http://bugzilla.opendarwin.org/show_bug.cgi?id=11015
        SVG handles em units incorrectly

        Calculate viewport coordinates at layout time, since
        at this point the font size is known and lengths depending
        on font sizes can be calculated correctly.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@16601 268f45cc-cd09-0410-ab3c-d52691b4dbfc