PushMessaging.UnregistrationReason UMA should count GCM Store resets

chrome/browser/push_messaging/push_messaging_service_impl.cc

Index: chrome/browser/push_messaging/push_messaging_service_impl.cc
diff --git a/chrome/browser/push_messaging/push_messaging_service_impl.cc b/chrome/browser/push_messaging/push_messaging_service_impl.cc
index 11c16f159f3b26278880eeffc71a63d486eb2cd8..afc649e57a592bcef11364cf6eabd86feab98ca3 100644
--- a/chrome/browser/push_messaging/push_messaging_service_impl.cc
+++ b/chrome/browser/push_messaging/push_messaging_service_impl.cc
@@ -255,6 +255,8 @@ void PushMessagingServiceImpl::ShutdownHandler() {
 void PushMessagingServiceImpl::OnStoreReset() {
   // Delete all cached subscriptions, since they are now invalid.
   for (const auto& identifier : PushMessagingAppIdentifier::GetAll(profile_)) {
+    RecordUnsubscribeReason(
+        content::PUSH_UNREGISTRATION_REASON_GCM_STORE_RESET);
     // Clear all the subscriptions in parallel, to reduce risk that shutdown
     // occurs before we finish clearing them.
     ClearPushSubscriptionId(profile_, identifier.origin(),