Bug 1193731: add missing handlers for icegatheringstatechange r=jib

MozReview-Commit-ID: ABWJfiImeYU

--HG--
extra : rebase_source : ee625d77bf972553352852617c26f0dbb37ca327

dom/media/PeerConnection.js

@@ -427,6 +427,7 @@ RTCPeerConnection.prototype = {
     this.makeGetterSetterEH("onremovestream");
     this.makeGetterSetterEH("ondatachannel");
     this.makeGetterSetterEH("oniceconnectionstatechange");
+    this.makeGetterSetterEH("onicegatheringstatechange");
     this.makeGetterSetterEH("onidentityresult");
     this.makeGetterSetterEH("onpeeridentity");
     this.makeGetterSetterEH("onidpassertionerror");
@@ -1213,6 +1214,7 @@ RTCPeerConnection.prototype = {
   changeIceGatheringState: function(state) {
     this._iceGatheringState = state;
     _globalPCList.notifyLifecycleObservers(this, "icegatheringstatechange");
+    this.dispatchEvent(new this._win.Event("icegatheringstatechange"));
   },
 
   changeIceConnectionState: function(state) {
@@ -1423,6 +1425,9 @@ PeerConnectionObserver.prototype = {
 
   handleIceConnectionStateChange: function(iceConnectionState) {
     let pc = this._dompc;
+    if (pc.iceConnectionState === iceConnectionState) {
+      return;
+    }
     if (pc.iceConnectionState === 'new') {
       var checking_histogram = Services.telemetry.getHistogramById("WEBRTC_ICE_CHECKING_RATE");
       if (iceConnectionState === 'checking') {
@@ -1455,15 +1460,19 @@ PeerConnectionObserver.prototype = {
   //   new        The object was just created, and no networking has occurred
   //              yet.
   //
-  //   gathering  The ICE engine is in the process of gathering candidates for
+  //   gathering  The ICE agent is in the process of gathering candidates for
   //              this RTCPeerConnection.
   //
-  //   complete   The ICE engine has completed gathering. Events such as adding
+  //   complete   The ICE agent has completed gathering. Events such as adding
   //              a new interface or a new TURN server will cause the state to
   //              go back to gathering.
   //
   handleIceGatheringStateChange: function(gatheringState) {
-    this._dompc.changeIceGatheringState(gatheringState);
+    let pc = this._dompc;
+    if (pc.iceGatheringState === gatheringState) {
+      return;
+    }
+    pc.changeIceGatheringState(gatheringState);
   },
 
   onStateChange: function(state) {