system_api: Add kReconnectParameterThirdPartyVpn for shill

This parameter is set by a Chrome vpnProvider app to tell shill that
it can handle platform messages that signal the need to re-establish
the VPN connection.  It allows us to extend the API in a backward-
compatible way.

BUG=chromium:514343
TEST=manual

Change-Id: I11b3b8d7f1c0ccec0ee22c1fd4d2ff887fba22c4
Reviewed-on: https://chromium-review.googlesource.com/328745
Commit-Ready: Kevin Cernekee <cernekee@chromium.org>
Tested-by: Kevin Cernekee <cernekee@chromium.org>
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
1 file changed