Fix race conditions on negotiation retry.

Don't start streaming until peerConnection.iceConnectionState is 'connected'. Previously, clients would attempt start streaming whenever a description or candidate was received. There are guards in place e.g. makingOffer and otherClient.streaming and I'd still like to figure out why this race condition still persisted, but this approach caused excessive calls to Client#streamTo.

app/assets/javascripts/controllers/room_controller.js

@@ -21,8 +21,8 @@ export default class RoomController extends Controller {
       clientId: this.client.id
     })
 
-    this.signaller.on('description candidate', ({ detail: { from } }) => {
-      this.startStreamingTo(this.clients[from])
+    this.client.on('iceConnection:connected', ({ detail: { otherClient } }) => {
+      this.startStreamingTo(otherClient)
     })
   }
 

app/assets/javascripts/models/webrtc_negotiation.js

@@ -148,8 +148,10 @@ export default class WebrtcNegotiation {
       })
     }
 
-    this._onconnectionstatechange = (event) => {
-      if (this.peerConnection.connectionState === 'connected') {
+    this._oniceconnectionstatechange = (event) => {
+      this.client.broadcast(`iceConnection:${this.peerConnection.iceConnectionState}`, { otherClient: this.otherClient })
+
+      if (this.peerConnection.iceConnectionState === 'connected') {
         this.retryCount = 0
       }
     }
@@ -158,15 +160,15 @@ export default class WebrtcNegotiation {
 
     this.peerConnection.addEventListener('negotiationneeded', this._onnegotiationneeded)
     this.peerConnection.addEventListener('icecandidate', this._onicecandidate)
-    this.peerConnection.addEventListener('connectionstatechange', this._onconnectionstatechange)
+    this.peerConnection.addEventListener('iceconnectionstatechange', this._oniceconnectionstatechange)
     this.peerConnection.addEventListener('track', this._ontrack)
   }
 
   teardownPeerConnection () {
     this.peerConnection.close()
     this.peerConnection.removeEventListener('negotiationneeded', this._onnegotiationneeded)
     this.peerConnection.removeEventListener('icecandidate', this._onicecandidate)
-    this.peerConnection.removeEventListener('connectionstatechange', this._onconnectionstatechange)
+    this.peerConnection.removeEventListener('iceconnectionstatechange', this._oniceconnectionstatechange)
     this.peerConnection.removeEventListener('track', this._ontrack)
     this.peerConnection = null
   }