Alarm: wakes up statsd and notifies the subscribers.

Test: manually tested it.
Change-Id: Id796a68976aeb1611183023ba4e9c6a8b8c44bb8
diff --git a/cmds/statsd/src/guardrail/StatsdStats.h b/cmds/statsd/src/guardrail/StatsdStats.h
index 8c16e4e..24ac688 100644
--- a/cmds/statsd/src/guardrail/StatsdStats.h
+++ b/cmds/statsd/src/guardrail/StatsdStats.h
@@ -170,6 +170,11 @@
     void noteRegisteredAnomalyAlarmChanged();
 
     /**
+     * Report that statsd modified the periodic alarm registered with StatsCompanionService.
+     */
+    void noteRegisteredPeriodicAlarmChanged();
+
+    /**
      * Records the number of snapshot and delta entries that are being dropped from the uid map.
      */
     void noteUidMapDropped(int snapshots, int deltas);
@@ -264,6 +269,9 @@
     // StatsCompanionService.
     int mAnomalyAlarmRegisteredStats = 0;
 
+    // Stores the number of times statsd registers the periodic alarm changes
+    int mPeriodicAlarmRegisteredStats = 0;
+
     // Stores the number of times an anomaly detection alert has been declared
     // (per config, per alert name). The map size is capped by kMaxConfigCount.
     std::map<const ConfigKey, std::map<const int64_t, int>> mAlertStats;