C++11 declares a type safe null pointer

content/common/android/surface_texture_peer.cc

 // Copyright (c) 2012 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 "content/common/android/surface_texture_peer.h"
 
 #include "base/logging.h"
 
 namespace content {
 
 namespace {
-SurfaceTexturePeer* g_instance_ = NULL;
+SurfaceTexturePeer* g_instance_ = nullptr;
 }  // namespace
 
 SurfaceTexturePeer::SurfaceTexturePeer() {
 }
 
 SurfaceTexturePeer::~SurfaceTexturePeer() {
 }
 
 // static
 SurfaceTexturePeer* SurfaceTexturePeer::GetInstance() {
   DCHECK(g_instance_);
   return g_instance_;
 }
 
 // static
 void SurfaceTexturePeer::InitInstance(SurfaceTexturePeer* instance) {
   DCHECK(!g_instance_);
   g_instance_ = instance;
 }
 
 }  // namespace content