[Password Manager Cleanup] Replaces NULL -> nullptr.

components/password_manager/core/browser/stub_password_manager_client.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/password_manager/core/browser/stub_password_manager_client.h"
 
 #include "base/memory/scoped_vector.h"
 #include "components/password_manager/core/browser/password_form_manager.h"
 
 namespace password_manager {
@@ skipping 35 matching lines @@
 
 void StubPasswordManagerClient::NotifyUserAutoSignin(
     ScopedVector<autofill::PasswordForm> local_forms) {
 }
 
 void StubPasswordManagerClient::AutomaticPasswordSave(
     scoped_ptr<PasswordFormManager> saved_manager) {
 }
 
 PrefService* StubPasswordManagerClient::GetPrefs() {
-  return NULL;
+  return nullptr;
 }
 
 PasswordStore* StubPasswordManagerClient::GetPasswordStore() const {
-  return NULL;
+  return nullptr;
 }
 
 }  // namespace password_manager