Add support to update_engine to poke Omaha after an update has been applied

update_check_scheduler.h

Index: update_check_scheduler.h
diff --git a/update_check_scheduler.h b/update_check_scheduler.h
index 181129149463363e29f9533d2b041ae86311c284..8239c0d7ef3147f188ba00fffa15c449f6b5a243 100644
--- a/update_check_scheduler.h
+++ b/update_check_scheduler.h
@@ -76,6 +76,7 @@ class UpdateCheckScheduler {
   FRIEND_TEST(UpdateCheckSchedulerTest, SetUpdateStatusNonIdleTest);
   FRIEND_TEST(UpdateCheckSchedulerTest, StaticCheckOOBECompleteTest);
   FRIEND_TEST(UpdateCheckSchedulerTest, StaticCheckOOBENotCompleteTest);
+  FRIEND_TEST(UpdateAttempterTest, PingOmahaTest);
 
   // Wraps GLib's g_timeout_add_seconds so that it can be mocked in tests.
   virtual guint GTimeoutAddSeconds(guint interval, GSourceFunc function);