[Sync] Avoid unregistering object IDs on shutdown

sync/notifier/non_blocking_invalidation_notifier.cc

Index: sync/notifier/non_blocking_invalidation_notifier.cc
diff --git a/sync/notifier/non_blocking_invalidation_notifier.cc b/sync/notifier/non_blocking_invalidation_notifier.cc
index ac0f76a2cb37fcaec0419add599e046f6adab1e3..615c745b32c80337672c7f3044ba2898e220be24 100644
--- a/sync/notifier/non_blocking_invalidation_notifier.cc
+++ b/sync/notifier/non_blocking_invalidation_notifier.cc
@@ -4,6 +4,8 @@
 
 #include "sync/notifier/non_blocking_invalidation_notifier.h"
 
+#include <cstddef>
+
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
@@ -15,6 +17,12 @@
 
 namespace syncer {
 
+namespace {
+
+const char kHandlerName[] = "NonBlockingInvalidationHandler";
+
+}  // namespace
+
 class NonBlockingInvalidationNotifier::Core
     : public base::RefCountedThreadSafe<NonBlockingInvalidationNotifier::Core>,
       // SyncNotifierObserver to observe the InvalidationNotifier we create.
@@ -89,12 +97,12 @@ void NonBlockingInvalidationNotifier::Core::Initialize(
           initial_invalidation_state,
           invalidation_state_tracker,
           client_info));
+  invalidation_notifier_->SetHandler(kHandlerName, this);
 }
 
-
 void NonBlockingInvalidationNotifier::Core::Teardown() {
   DCHECK(network_task_runner_->BelongsToCurrentThread());
-  invalidation_notifier_->UpdateRegisteredIds(this, ObjectIdSet());
+  invalidation_notifier_->SetHandler(kHandlerName, NULL);
   invalidation_notifier_.reset();
   network_task_runner_ = NULL;
 }
@@ -102,7 +110,7 @@ void NonBlockingInvalidationNotifier::Core::Teardown() {
 void NonBlockingInvalidationNotifier::Core::UpdateRegisteredIds(
     const ObjectIdSet& ids) {
   DCHECK(network_task_runner_->BelongsToCurrentThread());
-  invalidation_notifier_->UpdateRegisteredIds(this, ids);
+  invalidation_notifier_->UpdateRegisteredIds(kHandlerName, ids);
 }
 
 void NonBlockingInvalidationNotifier::Core::SetUniqueId(
@@ -183,11 +191,18 @@ NonBlockingInvalidationNotifier::~NonBlockingInvalidationNotifier() {
   }
 }
 
+void NonBlockingInvalidationNotifier::SetHandler(
+    const std::string& handler_name,
+    SyncNotifierObserver* handler) {
+  DCHECK(parent_task_runner_->BelongsToCurrentThread());
+  helper_.SetHandler(handler_name, handler);
+}
+
 void NonBlockingInvalidationNotifier::UpdateRegisteredIds(
-    SyncNotifierObserver* handler, const ObjectIdSet& ids) {
+    const std::string& handler_name, const ObjectIdSet& ids) {
   DCHECK(parent_task_runner_->BelongsToCurrentThread());
-  const ObjectIdSet& all_registered_ids =
-      helper_.UpdateRegisteredIds(handler, ids);
+  helper_.UpdateRegisteredIds(handler_name, ids);
+  const ObjectIdSet& all_registered_ids = helper_.GetAllRegisteredIds();
   if (!network_task_runner_->PostTask(
           FROM_HERE,
           base::Bind(