Bind a socket to a network if the network handle is set.

webrtc/base/network.h

Index: webrtc/base/network.h
diff --git a/webrtc/base/network.h b/webrtc/base/network.h
index 2f2e1b3a45aaf3e3592a37374f149f63e4f4d4b2..041b78cd4da6b7f6ecf44032d428992b47b5871b 100644
--- a/webrtc/base/network.h
+++ b/webrtc/base/network.h
@@ -255,7 +255,7 @@ class BasicNetworkManager : public NetworkManagerBase,
   int start_count_;
   std::vector<std::string> network_ignore_list_;
   bool ignore_non_default_routes_;
-  scoped_ptr<NetworkMonitorInterface> network_monitor_;
+  NetworkMonitorInterface* network_monitor_ = nullptr;
 };
 
 // Represents a Unix-type network interface, with a name and single address.