shill: vpn: Implement NSS database interface class.

Use the NSS class to lookup NSS certificates for OpenVPN.

BUG=chromium-os:28792
TEST=unit tests

Change-Id: I2e0c7924d664f375f5b01bc73506e2b91e6f8720
Reviewed-on: https://gerrit.chromium.org/gerrit/19457
Tested-by: Darin Petkov <petkov@chromium.org>
Reviewed-by: Paul Stewart <pstew@chromium.org>
Commit-Ready: Darin Petkov <petkov@chromium.org>
diff --git a/glib.cc b/glib.cc
index a2e9e07..a462ac7 100644
--- a/glib.cc
+++ b/glib.cc
@@ -224,6 +224,28 @@
   g_spawn_close_pid(pid);
 }
 
+gboolean GLib::SpawnSync(const gchar *working_directory,
+                         gchar **argv,
+                         gchar **envp,
+                         GSpawnFlags flags,
+                         GSpawnChildSetupFunc child_setup,
+                         gpointer user_data,
+                         gchar **standard_output,
+                         gchar **standard_error,
+                         gint *exit_status,
+                         GError **error) {
+  return g_spawn_sync(working_directory,
+                      argv,
+                      envp,
+                      flags,
+                      child_setup,
+                      user_data,
+                      standard_output,
+                      standard_error,
+                      exit_status,
+                      error);
+}
+
 void GLib::Strfreev(gchar **str_array) {
   g_strfreev(str_array);
 }