[acgiowt] (2) Catch up with recent changes that were made while the p…

…ipeline was down. Sorry for jamming all these changes into one patch.

Affected topics: Canvas, DOM APIs, HTML, HTML Syntax and Parsing, Microdata, Offline Web Applications, Video Text Tracks, Video and Audio, Workers

git-svn-id: http://svn.whatwg.org/webapps@8695 340c8d12-0b0e-0410-8428-c7bf67bfef74