[cssom] Rationale for including (or not) CSSCharsetRule

Hi Glenn and Anne

In  
http://dev.w3.org/cvsweb/~checkout~/csswg/cssom/Attic/Overview.html?rev=1.166;content-type=text%2Fhtml#history  
CSSCharsetRule was obsoleted because it was "not deemed necessary".

In https://dvcs.w3.org/hg/csswg/rev/961ed47ad0fc it was restored by Glenn.

I could not find any discussion about either of these decisions. If I  
missed it, please provide a pointer.

Could both of you please elaborate on the rationale regarding  
CSSCharsetRule?

If anyone else has opinions about CSSCharsetRule, please state them.

Thanks!
-- 
Simon Pieters
Opera Software