Use background thread for AsyncAudioDecoder

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

 /*
  * Copyright (C) 2011, 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
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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 #ifndef AsyncAudioDecoder_h
 #define AsyncAudioDecoder_h
 
 #include "platform/heap/Handle.h"
-#include "public/platform/WebThread.h"
 #include "wtf/build_config.h"
 #include <memory>
 
 namespace blink {
 
 class BaseAudioContext;
 class AudioBuffer;
 class AudioBufferCallback;
 class AudioBus;
 class DOMArrayBuffer;
 class ScriptPromiseResolver;
 
-// AsyncAudioDecoder asynchronously decodes audio file data from a DOMArrayBuffer in a worker thread.
-// Upon successful decoding, a completion callback will be invoked with the decoded PCM data in an AudioBuffer.
+// AsyncAudioDecoder asynchronously decodes audio file data from a
+// DOMArrayBuffer in the background thread. Upon successful decoding, a
+// completion callback will be invoked with the decoded PCM data in an
+// AudioBuffer.
 
 class AsyncAudioDecoder {
     DISALLOW_NEW();
     WTF_MAKE_NONCOPYABLE(AsyncAudioDecoder);
 public:
-    AsyncAudioDecoder();
-    ~AsyncAudioDecoder();
+    AsyncAudioDecoder() { };
+    ~AsyncAudioDecoder() { };
 
     // Must be called on the main thread.  |decodeAsync| and callees must not modify any of the
     // parameters except |audioData|.  They are used to associate this decoding instance with the
     // caller to process the decoding appropriately when finished.
     void decodeAsync(DOMArrayBuffer* audioData, float sampleRate, AudioBufferCallback* successCallback, AudioBufferCallback* errorCallback, ScriptPromiseResolver* , BaseAudioContext*);
 
 private:
     AudioBuffer* createAudioBufferFromAudioBus(AudioBus*);
-    static void decode(DOMArrayBuffer* audioData, float sampleRate, AudioBufferCallback* successCallback, AudioBufferCallback* errorCallback, ScriptPromiseResolver*, BaseAudioContext*);
+    static void decodeOnBackgroundThread(DOMArrayBuffer* audioData, float sampleRate, AudioBufferCallback* successCallback, AudioBufferCallback* errorCallback, ScriptPromiseResolver*, BaseAudioContext*);
     static void notifyComplete(DOMArrayBuffer* audioData, AudioBufferCallback* successCallback, AudioBufferCallback* errorCallback, AudioBus*, ScriptPromiseResolver*, BaseAudioContext*);
-
-    std::unique_ptr<WebThread> m_thread;
 };
 
 } // namespace blink
 
 #endif // AsyncAudioDecoder_h