Clear the channel and endpoint_id in SetAddress for the XMPP channel.

remoting/protocol/jingle_messages.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "remoting/protocol/jingle_messages.h"
 
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
 #include "remoting/base/constants.h"
 #include "remoting/protocol/content_description.h"
@@ skipping 183 matching lines @@
                     : "|endpoint_id| should be empty for XMPP channel");
     return empty_instance;
   }
 
   return SignalingAddress(jid, endpoint_id, channel);
 }
 
 void SetAddress(buzz::XmlElement* iqElement,
                 const SignalingAddress& address,
                 bool from) {
+  // Start from a fresh slate regardless of the previous address format.
+  iqElement->ClearAttr(GetQNameByField(Field::JID, from));
+  iqElement->ClearAttr(GetQNameByField(Field::CHANNEL, from));
+  iqElement->ClearAttr(GetQNameByField(Field::ENDPOINT_ID, from));
+
   if (address.empty()) {
     return;
   }
 
+  // Always set the JID.
   iqElement->AddAttr(GetQNameByField(Field::JID, from), address.jid);
 
+  // Only set the channel and endpoint_id in the LCS channel.
   if (address.channel == SignalingAddress::Channel::LCS) {
     iqElement->AddAttr(GetQNameByField(Field::ENDPOINT_ID, from),
                        address.endpoint_id);
     const char* channel_str = ValueToName(kChannelTypes, address.channel);
     iqElement->AddAttr(GetQNameByField(Field::CHANNEL, from), channel_str);
   }
 }
 
 }  // namespace
 
@@ skipping 373 matching lines @@
     result->AddElement(FormatIceCredentials(credentials));
   }
   for (const NamedCandidate& candidate : candidates) {
     result->AddElement(FormatIceCandidate(candidate));
   }
   return result;
 }
 
 }  // namespace protocol
 }  // namespace remoting