webrtc-pc

db52c871 - Enable trickling of end-of-candidates through addIceCandidate.

Enable trickling of end-of-candidates through addIceCandidate. A null parameter in addIceCandidate now represents end-of-candidates for all media sections. The definitions of the `failed` and `completed` ICE connection states have been updated so that they only occur when there are no more remote candidates. Also updated the example code that trickled candidates, such that the null candidate is trickled rather than ignored.