When doing continual gathering, remove local candidates when a network is dropped.

webrtc/base/network.cc

 /*
  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 299 matching lines @@
   if (merged_list.size() != networks_.size()) {
     *changed = true;
   }
 
   // If the network list changes, we re-assign |networks_| to the merged list
   // and re-sort it.
   if (*changed) {
     networks_ = merged_list;
     // Reset the active states of all networks.
     for (const auto& kv : networks_map_) {
-      kv.second->set_active(false);
-    }
-    for (Network* network : networks_) {
-      network->set_active(true);
+      Network* network = kv.second;
+      // If |network| is in the newly generated |networks_|, it is active.
+      bool found = std::find(networks_.begin(), networks_.end(), network) !=
+                   networks_.end();
+      network->set_active(found);
     }
     std::sort(networks_.begin(), networks_.end(), SortNetworks);
     // Now network interfaces are sorted, we should set the preference value
     // for each of the interfaces we are planning to use.
     // Preference order of network interfaces might have changed from previous
     // sorting due to addition of higher preference network interface.
     // Since we have already sorted the network interfaces based on our
     // requirements, we will just assign a preference value starting with 127,
     // in decreasing order.
     int pref = kHighestNetworkPreference;
@@ skipping 584 matching lines @@
   std::stringstream ss;
   // Print out the first space-terminated token of the network desc, plus
   // the IP address.
   ss << "Net[" << description_.substr(0, description_.find(' '))
      << ":" << prefix_.ToSensitiveString() << "/" << prefix_length_
      << ":" << AdapterTypeToString(type_) << "]";
   return ss.str();
 }
 
 }  // namespace rtc