[giow] (1) Add a couple of ImageData() constructors, and (in order to make that feasible) drop all the HD stuff on <canvas>.
Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=24301
Affected topics: Canvas, DOM APIs, Security

git-svn-id: http://svn.whatwg.org/webapps@8397 340c8d12-0b0e-0410-8428-c7bf67bfef74