AU: Implement server-dictated poll interval.

update_check_scheduler.h

Index: update_check_scheduler.h
diff --git a/update_check_scheduler.h b/update_check_scheduler.h
index 7253c5a1158cfcff95e359ba872ed4543993ec6f..e3158ed5e2395303bc83f6c2a30a9b8cc82b9908 100644
--- a/update_check_scheduler.h
+++ b/update_check_scheduler.h
@@ -49,10 +49,14 @@ class UpdateCheckScheduler {
   // Sets the new update status. This is invoked by UpdateAttempter.
   void SetUpdateStatus(UpdateStatus status);
 
+  void set_poll_interval(int interval) { poll_interval_ = interval; }
+
  private:
   friend class UpdateCheckSchedulerTest;
   FRIEND_TEST(UpdateCheckSchedulerTest, CanScheduleTest);
   FRIEND_TEST(UpdateCheckSchedulerTest, ComputeNextIntervalAndFuzzBackoffTest);
+  FRIEND_TEST(UpdateCheckSchedulerTest, ComputeNextIntervalAndFuzzPollTest);
+  FRIEND_TEST(UpdateCheckSchedulerTest, ComputeNextIntervalAndFuzzPriorityTest);
   FRIEND_TEST(UpdateCheckSchedulerTest, ComputeNextIntervalAndFuzzTest);
   FRIEND_TEST(UpdateCheckSchedulerTest, GTimeoutAddSecondsTest);
   FRIEND_TEST(UpdateCheckSchedulerTest, IsBootDeviceRemovableTest);
@@ -110,6 +114,9 @@ class UpdateCheckScheduler {
   // The timeout interval (before fuzzing) for the last update check.
   int last_interval_;
 
+  // Server dictated poll interval in seconds, if positive.
+  int poll_interval_;
+
   DISALLOW_COPY_AND_ASSIGN(UpdateCheckScheduler);
 };