shill: Add connection class
The connection class represents the snapshot of connectivity
state, including routing, address information and addressing.
It is able to apply itself as the "default" connection, by
setting routing table metrics and DNS resolver files.
BUG=chromium-os:19095
TEST=New unittest
Change-Id: I7021867ed8a8559db0e84f58a72692abaf105cad
Reviewed-on: http://gerrit.chromium.org/gerrit/5938
Reviewed-by: Chris Masone <cmasone@chromium.org>
Tested-by: Paul Stewart <pstew@chromium.org>
14 files changed