Add signaling to support ICE renomination.

webrtc/p2p/base/transportdescriptionfactory.h

Index: webrtc/p2p/base/transportdescriptionfactory.h
diff --git a/webrtc/p2p/base/transportdescriptionfactory.h b/webrtc/p2p/base/transportdescriptionfactory.h
index 828aa6d22c4f2fae6b0b7d233d2209d3095b9642..2dde5b12584b729f6a59963dedd76a82058fc942 100644
--- a/webrtc/p2p/base/transportdescriptionfactory.h
+++ b/webrtc/p2p/base/transportdescriptionfactory.h
@@ -21,9 +21,11 @@ class SSLIdentity;
 namespace cricket {
 
 struct TransportOptions {
-  TransportOptions() : ice_restart(false), prefer_passive_role(false) {}
-  bool ice_restart;
-  bool prefer_passive_role;
+  bool ice_restart = false;
+  bool prefer_passive_role = false;
+  // If true, ICE renomination is supported and will be used if it is also
+  // supported by the remote side.
+  bool enable_ice_renomination = false;
 };
 
 // Creates transport descriptions according to the supplied configuration.