Add signaling to support ICE renomination.

webrtc/p2p/base/transportdescriptionfactory.cc

Index: webrtc/p2p/base/transportdescriptionfactory.cc
diff --git a/webrtc/p2p/base/transportdescriptionfactory.cc b/webrtc/p2p/base/transportdescriptionfactory.cc
index e57b7e3efae3e30907e3d45fe01e7f6f5e95fe69..61e2a9f3463bc16472bcfcbd01ef0f3d412712b2 100644
--- a/webrtc/p2p/base/transportdescriptionfactory.cc
+++ b/webrtc/p2p/base/transportdescriptionfactory.cc
@@ -37,6 +37,9 @@ TransportDescription* TransportDescriptionFactory::CreateOffer(
     desc->ice_ufrag = current_description->ice_ufrag;
     desc->ice_pwd = current_description->ice_pwd;
   }
+  if (options.enable_ice_renomination) {
+    desc->AddOption(ICE_RENOMINATION_STR);
+  }
 
   // If we are trying to establish a secure transport, add a fingerprint.
   if (secure_ == SEC_ENABLED || secure_ == SEC_REQUIRED) {
@@ -71,6 +74,9 @@ TransportDescription* TransportDescriptionFactory::CreateAnswer(
     desc->ice_ufrag = current_description->ice_ufrag;
     desc->ice_pwd = current_description->ice_pwd;
   }
+  if (options.enable_ice_renomination) {
+    desc->AddOption(ICE_RENOMINATION_STR);
+  }
 
   // Negotiate security params.
   if (offer && offer->identity_fingerprint.get()) {