Remove AudioDeviceObserver and make ADM not inherit from the Module interface.

modules/audio_device/mac/audio_device_mac.h

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 135 matching lines @@
   virtual int32_t SetStereoPlayout(bool enable);
   virtual int32_t StereoPlayout(bool& enabled) const;
   virtual int32_t StereoRecordingIsAvailable(bool& available);
   virtual int32_t SetStereoRecording(bool enable);
   virtual int32_t StereoRecording(bool& enabled) const;
 
   // Delay information and control
   virtual int32_t PlayoutDelay(uint16_t& delayMS) const;
   virtual int32_t RecordingDelay(uint16_t& delayMS) const;
 
-  virtual bool PlayoutWarning() const;
-  virtual bool PlayoutError() const;
-  virtual bool RecordingWarning() const;
-  virtual bool RecordingError() const;
-  virtual void ClearPlayoutWarning();
-  virtual void ClearPlayoutError();
-  virtual void ClearRecordingWarning();
-  virtual void ClearRecordingError();
-
   virtual void AttachAudioBuffer(AudioDeviceBuffer* audioBuffer);
 
  private:
   virtual int32_t MicrophoneIsAvailable(bool& available);
   virtual int32_t SpeakerIsAvailable(bool& available);
 
   static void AtomicSet32(int32_t* theValue, int32_t newValue);
   static int32_t AtomicGet32(int32_t* theValue);
 
   static void logCAMsg(const rtc::LoggingSeverity sev,
@@ skipping 151 matching lines @@
 
   uint32_t _captureLatencyUs;
   uint32_t _renderLatencyUs;
 
   // Atomically set variables
   mutable int32_t _captureDelayUs;
   mutable int32_t _renderDelayUs;
 
   int32_t _renderDelayOffsetSamples;
 
-  uint16_t _playWarning;
-  uint16_t _playError;
-  uint16_t _recWarning;
-  uint16_t _recError;
-
   PaUtilRingBuffer* _paCaptureBuffer;
   PaUtilRingBuffer* _paRenderBuffer;
 
   semaphore_t _renderSemaphore;
   semaphore_t _captureSemaphore;
 
   int _captureBufSizeSamples;
   int _renderBufSizeSamples;
 
   // Typing detection
   // 0x5c is key "9", after that comes function keys.
   bool prev_key_state_[0x5d];
 
   int get_mic_volume_counter_ms_;
 };
 
 }  // namespace webrtc
 
 #endif  // MODULES_AUDIO_DEVICE_MAIN_SOURCE_MAC_AUDIO_DEVICE_MAC_H_