sync: Implement disabling of non blocking types

sync/internal_api/sync_core.cc

Index: sync/internal_api/sync_core.cc
diff --git a/sync/internal_api/sync_core.cc b/sync/internal_api/sync_core.cc
index 9c26095abd5ef7c5f915f34614c64bae1b598bfd..dbeb76d0038ae76f49eb672497b8a8fa2b180f23 100644
--- a/sync/internal_api/sync_core.cc
+++ b/sync/internal_api/sync_core.cc
@@ -25,6 +25,10 @@ void SyncCore::ConnectSyncTypeToCore(
   model_type_registry_->InitializeNonBlockingType(type, task_runner, processor);
 }
 
+void SyncCore::Disconnect(ModelType type) {
+  model_type_registry_->RemoveNonBlockingType(type);
+}
+
 base::WeakPtr<SyncCore> SyncCore::AsWeakPtr() {
   return weak_ptr_factory_.GetWeakPtr();
 }