[login_manager] Add stub DBus API for policy get/set

session_manager_service.cc

Index: session_manager_service.cc
diff --git a/session_manager_service.cc b/session_manager_service.cc
index ca195d8663487080ea4b1043caac8e5596d61a5a..d708ef1be3ff5b508b64271db640157f145f61fa 100644
--- a/session_manager_service.cc
+++ b/session_manager_service.cc
@@ -728,6 +728,18 @@ gboolean SessionManagerService::RetrieveProperty(gchar* name,
   return TRUE;
 }
 
+gboolean SessionManagerService::StorePolicy(gchar* policy_blob,
+                                            GArray* signature,
+                                            GError** error) {
+  return FALSE;
+}
+
+gboolean SessionManagerService::RetrievePolicy(gchar** OUT_policy_blob,
+                                               GArray** OUT_signature,
+                                               GError** error) {
+  return FALSE;
+}
+
 gboolean SessionManagerService::LockScreen(GError** error) {
   screen_locked_ = TRUE;
   system_->SendSignalToChromium(chromium::kLockScreenSignal, NULL);