Adds to the RTCConfiguration `ice_regather_interval_range` which, when
set, specifies the randomized delay between automatic runs of ICE
regathering. The regathering will occur on all networks and re-use the
existing ICE ufrag/password. New connections are established once the
candidates come back and WebRTC will automatically switch to the new
connection that corresponds to the currently selected connection.
Bug: webrtc:7969
Change-Id: I6bbf5439a48e285f704aed9f408631cba038c82b
Reviewed-on: https://chromium-review.googlesource.com/562505
Reviewed-by: Peter Thatcher <pthatcher@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#18978}
aa41f0cfa6