Replace NULL with nullptr or null in webrtc/base/.

webrtc/base/transformadapter.cc

 /*
  *  Copyright 2004 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 157 matching lines @@
   if (error)
     *error = error_;
   return SR_ERROR;
 }
 
 void
 TransformAdapter::Close() {
   if (!direction_read_ && (state_ == ST_PROCESSING)) {
     state_ = ST_FLUSHING;
     do {
-      Write(0, 0, NULL, NULL);
+      Write(0, 0, nullptr, nullptr);
     } while (state_ == ST_FLUSHING);
   }
   state_ = ST_COMPLETE;
   StreamAdapterInterface::Close();
 }
 
 bool TransformAdapter::GetAvailable(size_t* size) const {
   return false;
 }
 
 bool TransformAdapter::ReserveSize(size_t size) {
   return true;
 }
 
 bool TransformAdapter::Rewind() {
   return false;
 }
 
 } // namespace rtc