Ice gathering

[aboba]

Currently Section 2.7 states (in the definition of RTCIceGathererState):

"RTCIceGatherer objects gather upon construction"

This creates an issue for WebRTC 1.0 shims, which have to resort to tricks (such as waiting to attach the onlocalcandidate event handler until setLocalDescription() is called), so as to avoid ICE candidate events.

To enable better control it would be desirable to add a gather method to the RTCIceGatherer, as follows:

partial interface RTCIceGatherer {
void start (optional RTCIceGatherOptions options);
};

[aboba]

Related messages:
https://lists.w3.org/Archives/Public/public-ortc/2015Dec/0008.html
https://lists.w3.org/Archives/Public/public-ortc/2015Dec/0012.html