Introduce AudioBufferMemoryPool to avoid thrashing on audio buffers.

media/base/audio_buffer_converter.h

 // Copyright 2014 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.
 
 #ifndef MEDIA_BASE_AUDIO_BUFFER_CONVERTER_H_
 #define MEDIA_BASE_AUDIO_BUFFER_CONVERTER_H_
 
 #include <deque>
 #include <memory>
 
 #include "base/memory/ref_counted.h"
 #include "base/time/time.h"
+#include "media/base/audio_buffer.h"
 #include "media/base/audio_converter.h"
 #include "media/base/audio_parameters.h"
 #include "media/base/audio_timestamp_helper.h"
 #include "media/base/media_export.h"
 
 namespace media {
 
-class AudioBuffer;
 class AudioBus;
 
 // Takes AudioBuffers in any format and uses an AudioConverter to convert them
 // to a common format (usually the hardware output format).
 class MEDIA_EXPORT AudioBufferConverter : public AudioConverter::InputCallback {
  public:
   explicit AudioBufferConverter(const AudioParameters& output_params);
   ~AudioBufferConverter() override;
 
   void AddInput(const scoped_refptr<AudioBuffer>& buffer);
@@ skipping 60 matching lines @@
   // Ratio of sample rates, in/out.
   double io_sample_rate_ratio_;
 
   // Computes timestamps in terms of the output sample rate.
   AudioTimestampHelper timestamp_helper_;
 
   // Are we flushing everything, without regard for providing AudioConverter
   // full AudioBuses in ProvideInput()?
   bool is_flushing_;
 
+  // Pool to avoid thrashing memory when allocating AudioBuffers.
+  scoped_refptr<AudioBufferMemoryPool> pool_;
+
   // The AudioConverter which does the real work here.
   std::unique_ptr<AudioConverter> audio_converter_;
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_AUDIO_BUFFER_CONVERTER_H_