C++11 declares a type safe null pointer

content/common/gpu/media/v4l2_image_processor.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 <fcntl.h>
 #include <linux/videodev2.h>
 #include <poll.h>
 #include <sys/eventfd.h>
 #include <sys/ioctl.h>
 #include <sys/mman.h>
@@ skipping 492 matching lines @@
         // EAGAIN if we're just out of buffers to dequeue.
         break;
       }
       PLOG(ERROR) << "ioctl() failed: VIDIOC_DQBUF";
       NOTIFY_ERROR();
       return;
     }
     InputRecord& input_record = input_buffer_map_[dqbuf.index];
     DCHECK(input_record.at_device);
     input_record.at_device = false;
-    input_record.frame = NULL;
+    input_record.frame = nullptr;
     free_input_buffers_.push_back(dqbuf.index);
     input_buffer_queued_count_--;
   }
 
   // Dequeue completed output (VIDEO_CAPTURE) buffers, recycle to the free list.
   // Return the finished buffer to the client via the job ready callback.
   while (output_buffer_queued_count_ > 0) {
     DCHECK(output_streamon_);
     memset(&dqbuf, 0, sizeof(dqbuf));
     memset(&planes, 0, sizeof(planes));
@@ skipping 168 matching lines @@
   while (!input_queue_.empty())
     input_queue_.pop();
 
   while (!running_jobs_.empty())
     running_jobs_.pop();
 
   free_input_buffers_.clear();
   for (size_t i = 0; i < input_buffer_map_.size(); ++i) {
     InputRecord& input_record = input_buffer_map_[i];
     input_record.at_device = false;
-    input_record.frame = NULL;
+    input_record.frame = nullptr;
     free_input_buffers_.push_back(i);
   }
   input_buffer_queued_count_ = 0;
 
   free_output_buffers_.clear();
   for (size_t i = 0; i < output_buffer_map_.size(); ++i) {
     OutputRecord& output_record = output_buffer_map_[i];
     output_record.at_device = false;
     if (!output_record.at_client)
       free_output_buffers_.push_back(i);
   }
   output_buffer_queued_count_ = 0;
 
   return true;
 }
 
 }  // namespace content