Currently the new onboarding experience does not show up if the snippets pref (as well as the asrouter experiment pref) is set to false; we should ensure it is not tied to this pref, and remove any other obsolete prefs, when landing this for release.

As discussed with Kate, here's the approach we're going to take to try and not only separate onboarding pref from snippets, but also in general try to consolidate some of these asrouter prefs: 1. add an 'enabled' field to each of the providers in browser.newtabpage.activity-stream.asrouter.messageProviders (false by default) + an additional 'cohort' field to the onboarding provider. this cohort field will hold the integer that shield will target for different cohorts for future onboarding experiments. this allows us to remove asrouterOnboardingCohort pref 2. move the initialization of asrouter content out of snippets.js 3. change snippets.js to initialize old snippets check against browser.newtabpage.activity-stream.asrouter.messageProviders.snippets.enabled pref 4. change onboarding targeting JEXL expression to check browser.newtabpage.activity-stream.asrouter.messageProviders.onboarding.cohort

Commits pushed to master at https://github.com/mozilla/activity-stream https://github.com/mozilla/activity-stream/commit/4ad851b3bc9ab6eac25b09d238e5276ef9b674e9 Fix Bug 1476684 - Onboarding shouldn't be affected by snippets, experiment prefs https://github.com/mozilla/activity-stream/commit/248ff08f6cac5380bdc84d79148539ce1b217d64 Merge pull request #4338 from sarracini/bug_1476684 Fix Bug 1476684 - Onboarding shouldn't be affected by snippets experiment prefs