C++11 declares a type safe null pointer

content/common/gpu/media/gpu_video_decode_accelerator.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/gpu/media/gpu_video_decode_accelerator.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 58 matching lines @@
  public:
   explicit DebugAutoLock(base::Lock&) {}
 };
 #endif
 
 class GpuVideoDecodeAccelerator::MessageFilter : public IPC::MessageFilter {
  public:
   MessageFilter(GpuVideoDecodeAccelerator* owner, int32 host_route_id)
       : owner_(owner), host_route_id_(host_route_id) {}
 
-  virtual void OnChannelError() override { sender_ = NULL; }
+  virtual void OnChannelError() override { sender_ = nullptr; }
 
-  virtual void OnChannelClosing() override { sender_ = NULL; }
+  virtual void OnChannelClosing() override { sender_ = nullptr; }
 
   virtual void OnFilterAdded(IPC::Sender* sender) override {
     sender_ = sender;
   }
 
   virtual void OnFilterRemoved() override {
     // This will delete |owner_| and |this|.
     owner_->OnFilterRemoved();
   }
 
@@ skipping 415 matching lines @@
   return stub_->channel()->Send(message);
 }
 
 void GpuVideoDecodeAccelerator::SendCreateDecoderReply(IPC::Message* message,
                                                        bool succeeded) {
   GpuCommandBufferMsg_CreateVideoDecoder::WriteReplyParams(message, succeeded);
   Send(message);
 }
 
 }  // namespace content