Expose WebThread rendering only when AudioWorklet flag is enabled

third_party/WebKit/Source/platform/audio/AudioDestination.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
@@ skipping 56 matching lines @@
       PassRefPtr<SecurityOrigin>);
 
   // The actual render function (WebAudioDevice::RenderCallback) isochronously
   // invoked by the media renderer.
   void Render(const WebVector<float*>& destination_data,
               size_t number_of_frames,
               double delay,
               double delay_timestamp,
               size_t prior_frames_skipped) override;
 
-  // The actual render request to the WebAudio destination node. This triggers
-  // the WebAudio rendering pipe line on the web thread.
-  void RequestRenderOnWebThread(size_t frames_requested,
-                                size_t frames_to_render,
-                                double delay,
-                                double delay_timestamp,
-                                size_t prior_frames_skipped);
+  // The actual render request to the WebAudio destination node.
+  void RequestRender(size_t frames_requested,
+                     size_t frames_to_render,
+                     double delay,
+                     double delay_timestamp,
+                     size_t prior_frames_skipped);
 
   virtual void Start();
   virtual void Stop();
 
   // Getters must be accessed from the main thread.
   size_t CallbackBufferSize() const;
   bool IsPlaying();
 
   // TODO(hongchan): this should not be called by the rendering thread.
   double SampleRate() const { return web_audio_device_->SampleRate(); }
 
   // Returns the audio buffer size in frames used by the underlying audio
   // hardware.
   int FramesPerBuffer() const;
 
+  bool IsAudioWorkletEnabled() const { return is_audio_worklet_enabled; }
+
   // The information from the actual audio hardware. (via Platform::current)
   static float HardwareSampleRate();
   static unsigned long MaxChannelCount();
 
  private:
   // Check if the buffer size chosen by the WebAudioDevice is too large.
   bool CheckBufferSize();
 
   size_t HardwareBufferSize();
 
-  bool IsRenderingThread();
-
   // Accessed by the main thread.
   std::unique_ptr<WebAudioDevice> web_audio_device_;
   const unsigned number_of_output_channels_;
   size_t callback_buffer_size_;
   bool is_playing_;
 
   // Accessed by the device thread. Rendering thread for WebAudio graph.
   std::unique_ptr<WebThread> rendering_thread_;
 
   // Accessed by both threads: resolves the buffer size mismatch between the
   // WebAudio engine and the callback function from the actual audio device.
   std::unique_ptr<PushPullFIFO> fifo_;
 
   // Accessed by device thread: to pass the data from FIFO to the device.
   RefPtr<AudioBus> output_bus_;
 
   // Accessed by rendering thread: to push the rendered result from WebAudio
   // graph into the FIFO.
   RefPtr<AudioBus> render_bus_;
 
   // Accessed by rendering thread: the render callback function of WebAudio
   // engine. (i.e. DestinationNode)
   AudioIOCallback& callback_;
 
   // Accessed by rendering thread.
   size_t frames_elapsed_;
+
+  // For signle thread rendering pipe line.

[Raymond Toy, 2017/05/15 17:42:24]

"signle"

And the comment doesn't really explain what is_audio_worklet_enabled seems to
imply.  Fix the comment or the variable name.

+  const bool is_audio_worklet_enabled;
 };
 
 }  // namespace blink
 
 #endif  // AudioDestination_h