GitLab

This is a merged CL containing the PrivetV2SetupFlow, PrivetV2Session,
and PrivetV2SetupOperation interfaces.

BUG=372843

Review URL: https://codereview.chromium.org/299123003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@272647 0039d316-1c4b-4281-b951-d872f2087c98