Replace the guts of AudioRendererBase with calls to scaling algorithm.

chrome/renderer/media/audio_renderer_impl.h

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.  Use of this
 // source code is governed by a BSD-style license that can be found in the
 // LICENSE file.
 //
 // Audio rendering unit utilizing audio output stream provided by browser
 // process through IPC.
 //
 // Relationship of classes.
 //
 //    AudioRendererHost                AudioRendererImpl
@@ skipping 165 matching lines @@
 
   // Memory shared by the browser process for audio buffer.
   scoped_ptr<base::SharedMemory> shared_memory_;
   size_t shared_memory_size_;
 
   // Message loop for the IO thread.
   MessageLoop* io_loop_;
 
   // Protects:
   // - |stopped_|
-  // - |playback_rate_|
   // - |pending_request_|
   // - |request_timestamp_|
   // - |request_delay_|
   Lock lock_;
 
   // A flag that indicates this filter is called to stop.
   bool stopped_;
 
-  // Keeps the current playback rate.
-  float playback_rate_;
-
   // A flag that indicates an outstanding packet request.
   bool pending_request_;
 
   // The time when a request is made.
   base::Time request_timestamp_;
 
   // The delay for the requested packet to be played.
   base::TimeDelta request_delay_;
 
   // State variables for prerolling.
   bool prerolling_;
 
   // Remaining bytes for prerolling to complete.
   size_t preroll_bytes_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioRendererImpl);
 };
 
 #endif  // CHROME_RENDERER_MEDIA_AUDIO_RENDERER_IMPL_H_