Content Security Policy Level 3

2016-01-27: We think this needs review but not sure whom to assign it to.
2016-02-17: ACTION-2012 Janina to review.
2016-03-09: 9 March 2016 APA meeting Janina reports concern re script-based a11y tools could be blocked. Various others agree. Shane taking over ACTION-2012 for deeper review.
2016-08-03: Spec still churning, pinging feedback on actions. But discovered action closed in April with no comments.
2017-05-10: APA discussion of blocking bookmarklets. ACTION-2131 Michael to ask WebAppSec.