Fabrice Bellet authored Apr 12, 2016 and Olivier Crête committed Jun 21, 2017

When the agent has the role of the stun server, is in controlled mode,
and receives a pair with the "use-candidate" attribute set, it must find
a matching succeded or discovered pair in its conncheck list. This is
described in ICE spec 7.2.1.5, "Updating the Nominated Flag", item #1.
When a matching pair is in succeeded state, the agent must nominate the
valid pair (a discovered pair) constructed from section 7.1.3.2.2,
that's been created from this succeeded one. To make this lookup, we
introduce a new "discovered_pair" member of the CandidateCheckPair
struct, that links the succeeded pair, and its discovered pair
if any.

Differential Revision: https://phabricator.freedesktop.org/D878