Add signaling to support ICE renomination.

webrtc/api/peerconnectioninterface.h

Index: webrtc/api/peerconnectioninterface.h
diff --git a/webrtc/api/peerconnectioninterface.h b/webrtc/api/peerconnectioninterface.h
index fdf9cef51ec2a2a8b419227522d085a36b2c4ad2..221ed16d7f3d41c63f8174e6799d9635871c54ea 100644
--- a/webrtc/api/peerconnectioninterface.h
+++ b/webrtc/api/peerconnectioninterface.h
@@ -305,6 +305,10 @@ class PeerConnectionInterface : public rtc::RefCountInterface {
     // If set to true, this means the ICE transport should presume TURN-to-TURN
     // candidate pairs will succeed, even before a binding response is received.
     bool presume_writable_when_fully_relayed = false;
+
+    // If true, "renomination" will be added to the ice options in the transport
+    // description.
+    bool ice_renomination = false;
   };
 
   struct RTCOfferAnswerOptions {
@@ -314,18 +318,13 @@ class PeerConnectionInterface : public rtc::RefCountInterface {
     // The default value for constraint offerToReceiveX:true.
     static const int kOfferToReceiveMediaTrue = 1;
 
-    int offer_to_receive_video;
-    int offer_to_receive_audio;
-    bool voice_activity_detection;
-    bool ice_restart;
-    bool use_rtp_mux;
-
-    RTCOfferAnswerOptions()
-        : offer_to_receive_video(kUndefined),
-          offer_to_receive_audio(kUndefined),
-          voice_activity_detection(true),
-          ice_restart(false),
-          use_rtp_mux(true) {}
+    int offer_to_receive_video = kUndefined;
+    int offer_to_receive_audio = kUndefined;
+    bool voice_activity_detection = true;
+    bool ice_restart = false;
+    bool use_rtp_mux = true;
+
+    RTCOfferAnswerOptions() = default;
 
     RTCOfferAnswerOptions(int offer_to_receive_video,
                           int offer_to_receive_audio,