Add support for audio input mute detection on all platforms

media/audio/pulse/pulse_input.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_AUDIO_PULSE_PULSE_INPUT_H_
 #define MEDIA_AUDIO_PULSE_PULSE_INPUT_H_
 
+#include <pulse/pulseaudio.h>
 #include <string>
 
 #include "base/threading/thread_checker.h"
 #include "media/audio/agc_audio_stream.h"
 #include "media/audio/audio_device_name.h"
 #include "media/audio/audio_io.h"
 #include "media/audio/audio_parameters.h"
 #include "media/base/audio_block_fifo.h"
 
-struct pa_context;
-struct pa_source_info;
-struct pa_stream;
-struct pa_threaded_mainloop;
-
 namespace media {
 
 class AudioManagerPulse;
 
 class PulseAudioInputStream : public AgcAudioStream<AudioInputStream> {
  public:
   PulseAudioInputStream(AudioManagerPulse* audio_manager,
                         const std::string& device_name,
                         const AudioParameters& params,
                         pa_threaded_mainloop* mainloop,
                         pa_context* context);
 
   virtual ~PulseAudioInputStream();
 
   // Implementation of AudioInputStream.
   virtual bool Open() override;
   virtual void Start(AudioInputCallback* callback) override;
   virtual void Stop() override;
   virtual void Close() override;
   virtual double GetMaxVolume() override;
   virtual void SetVolume(double volume) override;
   virtual double GetVolume() override;
+  virtual bool IsMuted() override;
 
  private:
   // PulseAudio Callbacks.
   static void ReadCallback(pa_stream* handle, size_t length, void* user_data);
   static void StreamNotifyCallback(pa_stream* stream, void* user_data);
   static void VolumeCallback(pa_context* context, const pa_source_info* info,
                              int error, void* user_data);
+  static void MuteCallback(pa_context* context,
+                           const pa_source_info* info,
+                           int error,
+                           void* user_data);
 
   // Helper for the ReadCallback.
   void ReadData();
 
+  // Utility method used by GetVolume() and IsMuted().
+  bool GetSourceInformation(pa_source_info_cb_t callback);
+
   AudioManagerPulse* audio_manager_;
   AudioInputCallback* callback_;
   std::string device_name_;
   AudioParameters params_;
   int channels_;
   double volume_;
   bool stream_started_;
 
+  // Set to true in IsMuted() if user has muted the selected microphone in the
+  // sound settings UI.
+  bool muted_;
+
   // Holds the data from the OS.
   AudioBlockFifo fifo_;
 
   // PulseAudio API structs.
   pa_threaded_mainloop* pa_mainloop_; // Weak.
   pa_context* pa_context_;  // Weak.
   pa_stream* handle_;
 
   // Flag indicating the state of the context has been changed.
   bool context_state_changed_;
 
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(PulseAudioInputStream);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_PULSE_PULSE_INPUT_H_