cashew: reset local counter on plan transition

src/service_manager.h

Index: src/service_manager.h
diff --git a/src/service_manager.h b/src/service_manager.h
index 97fdee6cde5cc0e8d4cd8e20678c0115e417e2f0..264ff5f05d8143cd4480e89417102d8b4c99e6a8 100644
--- a/src/service_manager.h
+++ b/src/service_manager.h
@@ -70,6 +70,10 @@ class ServiceManager {
     // a child Service wants us to emit an update about its data plans
     virtual void EmitDataPlansUpdate(const Service& service) = 0;
 
+    // |plan|, associated with |service|, has become inactive
+    virtual void OnDataPlanInactive(const Service& service,
+                                    const DataPlan& plan) = 0;
+
     // factory
     static ServiceManager* NewServiceManager(
                                         DBus::Connection& connection,  // NOLINT