Replace NULL with nullptr or null in webrtc/audio/ and common_audio/.

webrtc/common_audio/resampler/resampler.cc

 /*
  *  Copyright (c) 2011 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 83 matching lines @@
 int Resampler::Reset(int inFreq, int outFreq, size_t num_channels)
 {
     if (num_channels != 1 && num_channels != 2) {
       return -1;
     }
     num_channels_ = num_channels;
 
     if (state1_)
     {
         free(state1_);
-        state1_ = NULL;
+        state1_ = nullptr;
     }
     if (state2_)
     {
         free(state2_);
-        state2_ = NULL;
+        state2_ = nullptr;
     }
     if (state3_)
     {
         free(state3_);
-        state3_ = NULL;
+        state3_ = nullptr;
     }
     if (in_buffer_)
     {
         free(in_buffer_);
-        in_buffer_ = NULL;
+        in_buffer_ = nullptr;
     }
     if (out_buffer_)
     {
         free(out_buffer_);
-        out_buffer_ = NULL;
+        out_buffer_ = nullptr;
     }
     if (slave_left_)
     {
         delete slave_left_;
-        slave_left_ = NULL;
+        slave_left_ = nullptr;
     }
     if (slave_right_)
     {
         delete slave_right_;
-        slave_right_ = NULL;
+        slave_right_ = nullptr;
     }
 
     in_buffer_size_ = 0;
     out_buffer_size_ = 0;
     in_buffer_size_max_ = 0;
     out_buffer_size_max_ = 0;
 
     // Start with a math exercise, Euclid's algorithm to find the gcd:
     int a = inFreq;
     int b = outFreq;
@@ skipping 805 matching lines @@
             outLen = (lengthIn * 8) / 11;
             free(tmp_mem);
             return 0;
             break;
 
     }
     return 0;
 }
 
 }  // namespace webrtc