Add module for counting date-last-roll-call and persisting those counts

components/update_client/update_client.h

Index: components/update_client/update_client.h
diff --git a/components/update_client/update_client.h b/components/update_client/update_client.h
index 06f4f09da36897c917a086c7c1e4bb75022a3c82..16df41c94992be80f0347953f738830d3f129679 100644
--- a/components/update_client/update_client.h
+++ b/components/update_client/update_client.h
@@ -128,6 +128,7 @@
 // being checked for updates and applying the update.
 
 class ComponentsUI;
+class PrefRegistrySimple;
 
 namespace base {
 class DictionaryValue;
@@ -330,6 +331,10 @@ class UpdateClient : public base::RefCounted<UpdateClient> {
 scoped_refptr<UpdateClient> UpdateClientFactory(
     const scoped_refptr<Configurator>& config);
 
+// This must be called prior to the construction of any Configurator that
+// contains a PrefService.
+void RegisterPrefs(PrefRegistrySimple* registry);
+
 }  // namespace update_client
 
 #endif  // COMPONENTS_UPDATE_CLIENT_UPDATE_CLIENT_H_