Replace NULL with nullptr in all C++ files.

webrtc/modules/desktop_capture/x11/x_server_pixel_buffer.cc

 /*
  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 50 matching lines @@
 
 XServerPixelBuffer::XServerPixelBuffer() {}
 
 XServerPixelBuffer::~XServerPixelBuffer() {
   Release();
 }
 
 void XServerPixelBuffer::Release() {
   if (x_image_) {
     XDestroyImage(x_image_);
-    x_image_ = NULL;
+    x_image_ = nullptr;
   }
   if (shm_pixmap_) {
     XFreePixmap(display_, shm_pixmap_);
     shm_pixmap_ = 0;
   }
   if (shm_gc_) {
     XFreeGC(display_, shm_gc_);
-    shm_gc_ = NULL;
+    shm_gc_ = nullptr;
   }
   if (shm_segment_info_) {
     if (shm_segment_info_->shmaddr != reinterpret_cast<char*>(-1))
       shmdt(shm_segment_info_->shmaddr);
     if (shm_segment_info_->shmid != -1)
       shmctl(shm_segment_info_->shmid, IPC_RMID, 0);
     delete shm_segment_info_;
-    shm_segment_info_ = NULL;
+    shm_segment_info_ = nullptr;
   }
   window_ = 0;
 }
 
 bool XServerPixelBuffer::Init(Display* display, Window window) {
   Release();
   display_ = display;
 
   XWindowAttributes attributes;
   {
@@ skipping 233 matching lines @@
       // Write as 32-bit RGB.
       dst_pos_32[x] = ((r >> 8) & 0xff0000) | ((g >> 16) & 0xff00) |
           ((b >> 24) & 0xff);
     }
     dst_pos += frame->stride();
     src_pos += src_stride;
   }
 }
 
 }  // namespace webrtc