Mix to an intermediate buffer.

services/media/audio/platform/linux/alsa_output.h

 // Copyright 2015 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 SERVICES_MEDIA_AUDIO_PLATFORM_LINUX_ALSA_OUTPUT_H_
 #define SERVICES_MEDIA_AUDIO_PLATFORM_LINUX_ALSA_OUTPUT_H_
 
 #include <alsa/asoundlib.h>
 #include <memory>
 
@@ skipping 18 matching lines @@
 
   // AudioOutput implementation
   MediaResult Init() override;
   void Cleanup() override;
 
   // StandardOutputBase implementation
   bool StartMixJob(MixJob* job, const LocalTime& process_start) override;
   bool FinishMixJob(const MixJob& job) override;
 
  private:
-  void FillMixBufWithSilence(uint32_t frames);
   void HandleAlsaError(snd_pcm_sframes_t code);
   void HandleAsError(snd_pcm_sframes_t code);
   void HandleAsUnderflow();
 
   snd_pcm_t* alsa_device_ = nullptr;
   snd_pcm_format_t alsa_format_;
 
   LinearTransform::Ratio frames_per_tick_;
-  uint8_t silence_byte_;
 
   std::unique_ptr<uint8_t> mix_buf_;
   uint32_t mix_buf_frames_;
 
   bool primed_ = false;
   bool local_to_output_known_ = false;
   LinearTransform local_to_output_;
   uint32_t local_to_output_gen_ = MixJob::INVALID_GENERATION + 1;
   int64_t frames_sent_;
 };
 
 }  // namespace audio
 }  // namespace media
 }  // namespace mojo
 
 #endif  // SERVICES_MEDIA_AUDIO_PLATFORM_LINUX_ALSA_OUTPUT_H_