buffet: Add periodic pings to XMPP connection

In order to monitor XMPP connection, we are implementing support
for XMPP pings described in XEP-0199 extension to XMPP standard
(see: http://xmpp.org/extensions/xep-0199.html#c2s).

Now we send ping requests to XMPP server every 60 seconds and if
we receive no response, we assume the connection is broken and
initiate immediate re-connection.

BUG=brillo:1138
TEST=`FEATURES=test emerge-link buffet`

Change-Id: Id2c092a0454b360d2c18bef5e30e3461ceeddab8
Reviewed-on: https://chromium-review.googlesource.com/274060
Reviewed-by: Vitaly Buka <vitalybuka@chromium.org>
Trybot-Ready: Alex Vakulenko <avakulenko@chromium.org>
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
3 files changed
tree: c82b83a5d89b1611a4d646a2995e7cf29aab3e1d
  1. buffet/