Implement suspend() and resume() for OfflineAudioContext

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 38 matching lines @@
     virtual void render(AudioBus* sourceBus, AudioBus* destinationBus, size_t numberOfFrames) override final;
 
     size_t currentSampleFrame() const { return acquireLoad(&m_currentSampleFrame); }
     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 quantizeTime(double) const { return 0; }

[Raymond Toy, 2015/05/28 16:37:35]

I think this is too vague.  Choose a more descriptive name.  Maybe
quantizeTimeToRenderingQuantum?  Add some comment on what this really does.

[hongchan, 2015/06/09 20:49:59]

Yes, I agree. Will fix it.

+
 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, ProcessingSizeInFrames)) // FIXME: handle non-stereo local input.
         {
         }
 
@@ skipping 29 matching lines @@
 
     unsigned long maxChannelCount() const;
 
 protected:
     AudioDestinationNode(AudioContext&);
 };
 
 } // namespace blink
 
 #endif // AudioDestinationNode_h