libweave: Move CommandObserver into public libweave interface

Clients will need to listen for Command changes.

BUG=brillo:1245
TEST='FEATURES=test emerge-gizmo buffet'

Change-Id: I1ba7339127f9d2789a0e09559a875cdc4ecb8df2
Reviewed-on: https://chromium-review.googlesource.com/287069
Tested-by: Vitaly Buka <vitalybuka@chromium.org>
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>
Commit-Queue: Vitaly Buka <vitalybuka@chromium.org>
8 files changed
tree: a85897d1684027ab8f3e7856081c55dc8e441e35
  1. buffet/
  2. libweave/