Use nullptr instead of 0 in WebAudio

Source/platform/audio/AudioBus.cpp

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 85 matching lines @@
 void AudioBus::zero()
 {
     for (unsigned i = 0; i < m_channels.size(); ++i)
         m_channels[i]->zero();
 }
 
 AudioChannel* AudioBus::channelByType(unsigned channelType)
 {
     // For now we only support canonical channel layouts...
     if (m_layout != LayoutCanonical)
-        return 0;
+        return nullptr;
 
     switch (numberOfChannels()) {
     case 1: // mono
         if (channelType == ChannelMono || channelType == ChannelLeft)
             return channel(0);
-        return 0;
+        return nullptr;
 
     case 2: // stereo
         switch (channelType) {
         case ChannelLeft: return channel(0);
         case ChannelRight: return channel(1);
-        default: return 0;
+        default: return nullptr;
         }
 
     case 4: // quad
         switch (channelType) {
         case ChannelLeft: return channel(0);
         case ChannelRight: return channel(1);
         case ChannelSurroundLeft: return channel(2);
         case ChannelSurroundRight: return channel(3);
-        default: return 0;
+        default: return nullptr;
         }
 
     case 5: // 5.0
         switch (channelType) {
         case ChannelLeft: return channel(0);
         case ChannelRight: return channel(1);
         case ChannelCenter: return channel(2);
         case ChannelSurroundLeft: return channel(3);
         case ChannelSurroundRight: return channel(4);
-        default: return 0;
+        default: return nullptr;
         }
 
     case 6: // 5.1
         switch (channelType) {
         case ChannelLeft: return channel(0);
         case ChannelRight: return channel(1);
         case ChannelCenter: return channel(2);
         case ChannelLFE: return channel(3);
         case ChannelSurroundLeft: return channel(4);
         case ChannelSurroundRight: return channel(5);
-        default: return 0;
+        default: return nullptr;
         }
     }
 
     ASSERT_NOT_REACHED();
-    return 0;
+    return nullptr;
 }
 
 const AudioChannel* AudioBus::channelByType(unsigned type) const
 {
     return const_cast<AudioBus*>(this)->channelByType(type);
 }
 
 // Returns true if the channel count and frame-size match.
 bool AudioBus::topologyMatches(const AudioBus& bus) const
 {
@@ skipping 506 matching lines @@
     // If the bus needs no conversion then return as is.
     if ((!mixToMono || audioBus->numberOfChannels() == 1) && audioBus->sampleRate() == sampleRate)
         return audioBus;
 
     return AudioBus::createBySampleRateConverting(audioBus.get(), mixToMono, sampleRate);
 }
 
 } // namespace blink
 
 #endif // ENABLE(WEB_AUDIO)