[Password Manager Cleanup] Replaces NULL -> nullptr.

chrome/browser/password_manager/test_password_store_service.cc

Index: chrome/browser/password_manager/test_password_store_service.cc
diff --git a/chrome/browser/password_manager/test_password_store_service.cc b/chrome/browser/password_manager/test_password_store_service.cc
index 7617d111bde46576a2c9e72fbcf384fd9bdefef3..af96bc3bf0cd168d50f1d22ae7e7805805ddf547 100644
--- a/chrome/browser/password_manager/test_password_store_service.cc
+++ b/chrome/browser/password_manager/test_password_store_service.cc
@@ -12,7 +12,7 @@ KeyedService* TestPasswordStoreService::Build(
   scoped_refptr<password_manager::PasswordStore> store(
       new password_manager::TestPasswordStore);
   if (!store.get() || !store->Init(syncer::SyncableService::StartSyncFlare()))
-    return NULL;
+    return nullptr;
   return new TestPasswordStoreService(store);
 }