The Director of the W3C, Tim Berners-Lee, has stated that playback of protected content (i.e. DRM) is in scope for HTML5.  This was further confirmed in the charter on 20th September. 
According to the Director,
"While the W3C Team do believe that use cases like premium content should be addressed in the Open Web Platform in order to bring it to its full potential, we're also looking forward for the HTML Working Group to address any technical concerns raised against the EME draft."