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

webrtc/base/network.cc

Index: webrtc/base/network.cc
diff --git a/webrtc/base/network.cc b/webrtc/base/network.cc
index 152bcdf671f38d7ac0e0a1a12b24300bab5d64fe..d2b353160cce653d2b784bf0afb014ee95cde7c3 100644
--- a/webrtc/base/network.cc
+++ b/webrtc/base/network.cc
@@ -761,10 +761,9 @@ void BasicNetworkManager::StartNetworkMonitor() {
     if (!network_monitor_) {
       return;
     }
+    network_monitor_->SignalNetworksChanged.connect(
+        this, &BasicNetworkManager::OnNetworksChanged);
   }
-
-  network_monitor_->SignalNetworksChanged.connect(
-      this, &BasicNetworkManager::OnNetworksChanged);
   network_monitor_->Start();
 }