AU: Simplify the automatic update check code a little.

Moves automatic update checks into the UpdateAttempter class.
This is in preparation for resolving 2394.

BUG=2394
TEST=unit tests, gmerged on device

Change-Id: I66ddf860cc7e19334187dc7f1892ead53fc936c6

Review URL: http://codereview.chromium.org/3167039
diff --git a/update_attempter.h b/update_attempter.h
index b2ef371..1c9ad40 100644
--- a/update_attempter.h
+++ b/update_attempter.h
@@ -88,6 +88,13 @@
   // UPDATED_NEED_REBOOT. Returns true on sucess, false otherwise.
   bool RebootIfNeeded();
 
+  // Kicks off the periodic update checks, if necessary.
+  void InitiatePeriodicUpdateChecks();
+
+  // Schedules the next periodic update check |seconds| from now. Note
+  // that the actual timeout will be fuzzed.
+  void SchedulePeriodicUpdateCheck(int seconds);
+
   // DownloadActionDelegate methods
   void SetDownloadStatus(bool active);
   void BytesReceived(uint64_t bytes_received, uint64_t total);