ScriptProcessor buffer size should be consistent with callback size

third_party/WebKit/Source/modules/webaudio/AudioDestinationNode.h

 /*
  * 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 47 matching lines @@
   }
   double currentTime() const {
     return currentSampleFrame() / static_cast<double>(sampleRate());
   }
 
   virtual unsigned long maxChannelCount() const { return 0; }
 
   virtual void startRendering() = 0;
   virtual void stopRendering() = 0;
 
+  virtual size_t callbackBufferSize() const { return 0; }

[hongchan, 2016/12/20 20:35:13]

The comment is needed here. We have many 'callbacks' and 'buffers' in the code,
so it is good to specify what it is for.

[Raymond Toy, 2016/12/20 21:55:31]

Done.

And also made it pure virtual as we discussed.

+
  protected:
   // LocalAudioInputProvider allows us to expose an AudioSourceProvider for
   // local/live audio input.  If there is local/live audio input, we call set()
   // with the audio input data every render quantum.
   class LocalAudioInputProvider final : public AudioSourceProvider {
    public:
     LocalAudioInputProvider()
         : m_sourceBus(AudioBus::create(
               2,
               AudioUtilities::kRenderQuantumFrames))  // FIXME: handle
@@ skipping 26 matching lines @@
   LocalAudioInputProvider m_localAudioInputProvider;
 };
 
 class AudioDestinationNode : public AudioNode {
   DEFINE_WRAPPERTYPEINFO();
 
  public:
   AudioDestinationHandler& audioDestinationHandler() const;
 
   unsigned long maxChannelCount() const;
+  size_t callbackBufferSize() const { return handler().callbackBufferSize(); }

[hongchan, 2016/12/20 20:35:12]

Just curious: does this change dynamically? if not, can we just populate it at
the instantiation?

[Raymond Toy, 2016/12/20 21:55:31]

Don't think this can change dynamically.  Might be able to populate it at
instantiation, but the derived classes are the only ones who know what the value
should be, so they need to be queried anyway.

 
  protected:
   AudioDestinationNode(BaseAudioContext&);
 };
 
 }  // namespace blink
 
 #endif  // AudioDestinationNode_h