Introduce AudioOutputResampler for browser side resampling.

media/base/multi_channel_resampler.h

 // Copyright (c) 2012 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_MULTI_CHANNEL_RESAMPLER_H_
 #define MEDIA_BASE_MULTI_CHANNEL_RESAMPLER_H_
 
 #include <vector>
 
 #include "base/callback.h"
@@ skipping 16 matching lines @@
   // Constructs a MultiChannelResampler with the specified |read_cb|, which is
   // used to acquire audio data for resampling.  |io_sample_rate_ratio| is the
   // ratio of input / output sample rates.
   MultiChannelResampler(int channels, double io_sample_rate_ratio,
                         const ReadCB& read_cb);
   virtual ~MultiChannelResampler();
 
   // Resamples |frames| of data from |read_cb_| into AudioBus.
   void Resample(AudioBus* audio_bus, int frames);
 
+  // Flush all buffered data and reset internal indexes.

[scherkus (not reviewing), 2012/09/07 13:30:17]

s/indexes/indicies/

$ git grep -i "indexes" . | wc -l
     995
$ git grep -i "indices" . | wc -l
    2619

[DaleCurtis, 2012/09/10 12:06:24]

Done.

+  void Flush();
+
  private:
+  friend class MultiChannelResamplerTest;

[scherkus (not reviewing), 2012/09/07 13:30:17]

hrmm.. friend only for last_frame_count_?

I'd either just ignore having a test for that or if you really want to test it
provide a last_frame_count_for_test() method

[DaleCurtis, 2012/09/10 12:06:24]

Removed.

+
   // SincResampler::ReadCB implementation.  ProvideInput() will be called for
   // each channel (in channel order) as SincResampler needs more data.
   void ProvideInput(int channel, float* destination, int frames);
 
   // Sanity check to ensure that ProvideInput() retrieves the same number of
   // frames for every channel.
   int last_frame_count_;
 
   // Source of data for resampling.
   ReadCB read_cb_;
 
   // Each channel has its own high quality resampler.
   ScopedVector<SincResampler> resamplers_;
 
   // Buffers for audio data going into SincResampler from ReadCB.
   scoped_ptr<AudioBus> resampler_audio_bus_;
   scoped_ptr<AudioBus> wrapped_resampler_audio_bus_;
   std::vector<float*> resampler_audio_data_;
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_MULTI_CHANNEL_RESAMPLER_H_