shill: vpn: Implement L2TPIPSecDriver::Connect and GetSec callback.

BUG=chromium-os:26843,chromium-os:29367
TEST=unit tests

Change-Id: I3a04c118da0b4c397b851ff69625461be455d135
Reviewed-on: https://gerrit.chromium.org/gerrit/20679
Reviewed-by: Darin Petkov <petkov@chromium.org>
Tested-by: Darin Petkov <petkov@chromium.org>
Commit-Ready: Darin Petkov <petkov@chromium.org>
diff --git a/openvpn_driver.h b/openvpn_driver.h
index 93a630e..a87abe1 100644
--- a/openvpn_driver.h
+++ b/openvpn_driver.h
@@ -160,6 +160,7 @@
   static void OnOpenVPNDied(GPid pid, gint status, gpointer data);
 
   // Implements RPCTaskDelegate.
+  virtual void GetLogin(std::string *user, std::string *password);
   virtual void Notify(const std::string &reason,
                       const std::map<std::string, std::string> &dict);