Add support for audio input mute detection on all platforms

components/copresence/mediums/audio/audio_recorder_unittest.cc

 // 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.
 
 #include "components/copresence/mediums/audio/audio_recorder.h"
 
 #include "base/bind.h"
 #include "base/memory/aligned_memory.h"
 #include "base/run_loop.h"
 #include "components/copresence/public/copresence_constants.h"
@@ skipping 29 matching lines @@
         base::Bind(&TestAudioInputStream::SimulateRecording,
                    base::Unretained(this)));
   }
   virtual void Stop() override {}
   virtual void Close() override {}
   virtual double GetMaxVolume() override { return 1.0; }
   virtual void SetVolume(double volume) override {}
   virtual double GetVolume() override { return 1.0; }
   virtual void SetAutomaticGainControl(bool enabled) override {}
   virtual bool GetAutomaticGainControl() override { return true; }
+  virtual bool IsMuted() override { return false; }
 
  private:
   void SimulateRecording() {
     const int fpb = params_.frames_per_buffer();
     for (int i = 0; i < buffer_->frames() / fpb; ++i) {
       scoped_ptr<media::AudioBus> source = media::AudioBus::Create(2, fpb);
       buffer_->CopyPartialFramesTo(i * fpb, fpb, 0, source.get());
       callback_->OnData(this, source.get(), fpb, 1.0);
     }
   }
@@ skipping 183 matching lines @@
       kDefaultChannels, kDefaultSampleRate, kDefaultBitsPerSample, kNumSamples);
 
   RecordAndVerifySamples();
 
   DeleteRecorder();
 }
 
 // TODO(rkc): Add tests with recording different sample rates.
 
 }  // namespace copresence