See their recent meeting minutes for some details:
http://www.w3.org/2011/02/23-webperf-minutes.html#item01 http://www.w3.org/2011/02/23-webperf-minutes.html#item02 -Art Barstow [WebPerf] http://www.w3.org/2010/webperf/
FYI, the Web Performance WG [WebPerf] intends to add Visibility API,
Yield and Continue, requestAnimationFrame to their Charter when it is
renewed/updated (in the next month or two):
