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

modules/audio_device/include/audio_device_defines.h

 /*
  *  Copyright (c) 2011 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.
  */
 
 #ifndef MODULES_AUDIO_DEVICE_INCLUDE_AUDIO_DEVICE_DEFINES_H_
 #define MODULES_AUDIO_DEVICE_INCLUDE_AUDIO_DEVICE_DEFINES_H_
 
 #include <stddef.h>
 
 #include "typedefs.h"  // NOLINT(build/include)
 
 namespace webrtc {
 
 static const int kAdmMaxDeviceNameSize = 128;
 static const int kAdmMaxFileNameSize = 512;
 static const int kAdmMaxGuidSize = 128;
 
 static const int kAdmMinPlayoutBufferSizeMs = 10;
 static const int kAdmMaxPlayoutBufferSizeMs = 250;
 
 // ----------------------------------------------------------------------------
-//  AudioDeviceObserver
-// ----------------------------------------------------------------------------
-
-class AudioDeviceObserver {
- public:
-  enum ErrorCode { kRecordingError = 0, kPlayoutError = 1 };
-  enum WarningCode { kRecordingWarning = 0, kPlayoutWarning = 1 };
-
-  virtual void OnErrorIsReported(const ErrorCode error) = 0;
-  virtual void OnWarningIsReported(const WarningCode warning) = 0;
-
- protected:
-  virtual ~AudioDeviceObserver() {}
-};
-
-// ----------------------------------------------------------------------------
 //  AudioTransport
 // ----------------------------------------------------------------------------
 
 class AudioTransport {
  public:
   virtual int32_t RecordedDataIsAvailable(const void* audioSamples,
                                           const size_t nSamples,
                                           const size_t nBytesPerSample,
                                           const size_t nChannels,
                                           const uint32_t samplesPerSec,
@@ skipping 105 matching lines @@
  private:
   int sample_rate_;
   size_t channels_;
   size_t frames_per_buffer_;
   size_t frames_per_10ms_buffer_;
 };
 
 }  // namespace webrtc
 
 #endif  // MODULES_AUDIO_DEVICE_INCLUDE_AUDIO_DEVICE_DEFINES_H_