Add field trial that records if multiprofiles is allowed for a ChromeOS session.

(Note that this doesn't mean more than one profile was actually used.)

BUG=218627

Review URL: https://codereview.chromium.org/159423002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250600 0039d316-1c4b-4281-b951-d872f2087c98
[Hotword] Simplify hotword description string and reflect new policy.

BUG=325439, 289023

Review URL: https://codereview.chromium.org/136303011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250601 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 250601