Extract the handling of the clean exit beacon from MetricsService. The extracted implementation sup…

components/metrics/metrics_service.h

Index: components/metrics/metrics_service.h
diff --git a/components/metrics/metrics_service.h b/components/metrics/metrics_service.h
index fb92e9b269bbb43cc9c6446672ad369547a7a7b5..cadaac0d1ac45bd95305744f2f3c50717f60216e 100644
--- a/components/metrics/metrics_service.h
+++ b/components/metrics/metrics_service.h
@@ -22,6 +22,7 @@
 #include "base/metrics/histogram_snapshot_manager.h"
 #include "base/metrics/user_metrics.h"
 #include "base/time/time.h"
+#include "components/metrics/clean_exit_beacon.h"
 #include "components/metrics/metrics_log.h"
 #include "components/metrics/metrics_log_manager.h"
 #include "components/metrics/metrics_provider.h"
@@ -386,6 +387,8 @@ class MetricsService : public base::HistogramFlattener {
 
   PrefService* local_state_;
 
+  CleanExitBeacon clean_exit_beacon_;
+
   base::ActionCallback action_callback_;
 
   // Indicate whether recording and reporting are currently happening.