Do not reconnect the network change signal each time the network manager is started

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 743 matching lines @@
 void BasicNetworkManager::StartNetworkMonitor() {
   NetworkMonitorFactory* factory = NetworkMonitorFactory::GetFactory();
   if (factory == nullptr) {
     return;
   }
   if (!network_monitor_) {
     network_monitor_.reset(factory->CreateNetworkMonitor());
     if (!network_monitor_) {
       return;
     }
+    network_monitor_->SignalNetworksChanged.connect(
+        this, &BasicNetworkManager::OnNetworksChanged);
   }
-
-  network_monitor_->SignalNetworksChanged.connect(
-      this, &BasicNetworkManager::OnNetworksChanged);
   network_monitor_->Start();
 }
 
 void BasicNetworkManager::StopNetworkMonitor() {
   if (!network_monitor_) {
     return;
   }
   network_monitor_->Stop();
 }
 
@@ skipping 198 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