be37888b6d
Added `RestartLocalTracks` and `RestartRemoteTracks` methods to `MediaStreamHandlerContainer` which will redo the track handlers' initial setup; most importantly, this will re-connect the renderer/capturer/etc. to a channel which was destroyed and then re-created. Also added `AcceptRemoteTracks` method to MediaStreamSignaling, which does the inverse of `RejectRemoteTracks`. Effectively this will notify sinks that the track is live again, after previously being set to `kEnded` when it was rejected. BUG=webrtc:2136 Review URL: https://codereview.webrtc.org/1231613002 Cr-Commit-Position: refs/heads/master@{#9600}