Gather stability prefs into managing objects.

components/metrics/clean_exit_beacon.h

Index: components/metrics/clean_exit_beacon.h
diff --git a/components/metrics/clean_exit_beacon.h b/components/metrics/clean_exit_beacon.h
index 6b896fa17845a39afb490c123bf7b2cb0f4c2c0d..e863e41e295f021b422ebcb0c087f5bbee6e1c44 100644
--- a/components/metrics/clean_exit_beacon.h
+++ b/components/metrics/clean_exit_beacon.h
@@ -8,6 +8,7 @@
 #include "base/macros.h"
 #include "base/strings/string16.h"
 
+class PrefRegistrySimple;
 class PrefService;
 
 namespace metrics {
@@ -32,6 +33,9 @@ class CleanExitBeacon {
   // Writes the provided beacon value.
   void WriteBeaconValue(bool exited_cleanly);
 
+  // Registers local state prefs used by this class.
+  static void RegisterPrefs(PrefRegistrySimple* registry);
+
  private:
   PrefService* const local_state_;
   const bool initial_value_;