Move NetworkStateNotifier and NetworkConnect from src/ui

chromeos/network/network_connection_handler.h

Index: chromeos/network/network_connection_handler.h
diff --git a/chromeos/network/network_connection_handler.h b/chromeos/network/network_connection_handler.h
index 623ab24b12bdca4915feebfdaec288646f05a755..af76d47fa4d42c545a138353c8837a6b9085eccd 100644
--- a/chromeos/network/network_connection_handler.h
+++ b/chromeos/network/network_connection_handler.h
@@ -99,6 +99,9 @@ class CHROMEOS_EXPORT NetworkConnectionHandler
   // Trying to configure an unmanged network but policy prohibits that
   static const char kErrorUnmanagedNetwork[];
 
+  // Network activation failed.
+  static const char kErrorActivateFailed[];
+
   ~NetworkConnectionHandler() override;
 
   void AddObserver(NetworkConnectionObserver* observer);