Removed a using declaration to avoid name conflicts
https://bugs.webkit.org/show_bug.cgi?id=112752

Reviewed by Ryosuke Niwa.

* html/ClassList.cpp: Put the using declaration here instead.

* html/ClassList.h: Don't put a using declaration in this header because
it can cause name conflicts with SVGNames.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@146273 268f45cc-cd09-0410-ab3c-d52691b4dbfc