0ed85b2ee3
RFC 5245 allows an ICE restart to occur on only one media section. However, before this CL, if an endpoint attempted to do this, we would change our local ICE ufrag/pwd in every media section. Also did some refactoring, turning the transport options from mediasesion.h into a map. Review URL: https://codereview.webrtc.org/1671173002 Cr-Commit-Position: refs/heads/master@{#11728}