The network preference is added to RTCConfiguration and passed to ICE. ICE considers now the preference set by applications over network interface types when making decisions in candidate pair switching. Bug: webrtc:8816 Change-Id: I40d2612705b54c83dd45772ac855808e0a76b1e1 Reviewed-on: https://webrtc-review.googlesource.com/44020 Commit-Queue: Qingsi Wang <qingsi@google.com> Reviewed-by: Sami Kalliomäki <sakal@webrtc.org> Reviewed-by: Taylor Brandstetter <deadbeef@webrtc.org> Cr-Commit-Position: refs/heads/master@{#21855}