AU: More UpdateAttempter unit tests.

BUG=6243
TEST=unit tests

Change-Id: I364cf8f4744098e45a6537bb89c6cabf92f3889c

Review URL: http://codereview.chromium.org/5301002
diff --git a/update_check_scheduler.h b/update_check_scheduler.h
index 2ba5253..1811291 100644
--- a/update_check_scheduler.h
+++ b/update_check_scheduler.h
@@ -50,6 +50,7 @@
   void SetUpdateStatus(UpdateStatus status);
 
   void set_poll_interval(int interval) { poll_interval_ = interval; }
+  int poll_interval() const { return poll_interval_; }
 
  private:
   friend class UpdateCheckSchedulerTest;