Fix potential crashes in NetworkHandler code

chromeos/network/network_connection_handler.h

 // 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.
 
 #ifndef CHROMEOS_NETWORK_NETWORK_CONNECTION_HANDLER_H_
 #define CHROMEOS_NETWORK_NETWORK_CONNECTION_HANDLER_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 215 matching lines @@
   // Calls Shill.Manager.Disconnect asynchronously.
   void CallShillDisconnect(
       const std::string& service_path,
       const base::Closure& success_callback,
       const network_handler::ErrorCallback& error_callback);
 
   // Handle success from Shill.Service.Disconnect.
   void HandleShillDisconnectSuccess(const std::string& service_path,
                                     const base::Closure& success_callback);
 
-  base::ObserverList<NetworkConnectionObserver> observers_;
+  base::ObserverList<NetworkConnectionObserver, true> observers_;
 
   // Local references to the associated handler instances.
   CertLoader* cert_loader_;
   NetworkStateHandler* network_state_handler_;
   NetworkConfigurationHandler* configuration_handler_;
   ManagedNetworkConfigurationHandler* managed_configuration_handler_;
 
   // Map of pending connect requests, used to prevent repeated attempts while
   // waiting for Shill and to trigger callbacks on eventual success or failure.
   std::map<std::string, ConnectRequest> pending_requests_;
   scoped_ptr<ConnectRequest> queued_connect_;
 
   // Track certificate loading state.
   bool logged_in_;
   bool certificates_loaded_;
   base::TimeTicks logged_in_time_;
 
   DISALLOW_COPY_AND_ASSIGN(NetworkConnectionHandler);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_NETWORK_NETWORK_CONNECTION_HANDLER_H_