arc: Handle PAI (PlayAutoInstall) flow state.

This handles PAI flow state and perform retry of PAI flow in case of
error. This also adds extra UMA stats describing PAI flow.

TEST=Locally
BUG=b:65594710

Change-Id: If9070ed69742f96749f0520e71d1e195705df28c
Reviewed-on: https://chromium-review.googlesource.com/c/1395718
Commit-Queue: Yury Khmel <khmel@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Reviewed-by: Greg Kerr <kerrnel@chromium.org>
Reviewed-by: Josh Horwich <jhorwich@chromium.org>
Reviewed-by: Yusuke Sato <yusukes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#622267}
13 files changed