Update prflx candidates' generation when setting ICE credentials.

webrtc/p2p/base/p2ptransportchannel.cc

Index: webrtc/p2p/base/p2ptransportchannel.cc
diff --git a/webrtc/p2p/base/p2ptransportchannel.cc b/webrtc/p2p/base/p2ptransportchannel.cc
index 66532411b29f5241c6b0f163d87c91d7ba9cbe2a..8fb33e58cb99934351c1f4c14de77f3dec0d1509 100644
--- a/webrtc/p2p/base/p2ptransportchannel.cc
+++ b/webrtc/p2p/base/p2ptransportchannel.cc
@@ -390,10 +390,13 @@ void P2PTransportChannel::SetRemoteIceCredentials(const std::string& ice_ufrag,
       candidate.set_password(ice_pwd);
     }
   }
-  // We need to update the credentials for any peer reflexive candidates.
+  // We need to update the credentials and generation for any peer reflexive
+  // candidates.
   for (Connection* conn : connections_) {
-    conn->MaybeSetRemoteIceCredentials(ice_ufrag, ice_pwd);
+    conn->MaybeSetRemoteIceCredentialsAndGeneration(remote_ice_parameters_);
   }
+  // Updating the remote ICE candidate generation could change the sort order.
+  RequestSort();
 }
 
 void P2PTransportChannel::SetRemoteIceMode(IceMode mode) {