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

modules/audio_device/win/audio_device_core_win.h

Index: modules/audio_device/win/audio_device_core_win.h
diff --git a/modules/audio_device/win/audio_device_core_win.h b/modules/audio_device/win/audio_device_core_win.h
index d4bf4738c8f23748585050f12a7618c2c286985f..6d94acefd17446a0227002619fdacf1a816c754a 100644
--- a/modules/audio_device/win/audio_device_core_win.h
+++ b/modules/audio_device/win/audio_device_core_win.h
@@ -177,16 +177,6 @@ public:
 
     virtual int32_t EnableBuiltInAEC(bool enable);
 
-public:
-    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();
-
 public:
     virtual void AttachAudioBuffer(AudioDeviceBuffer* audioBuffer);
 
@@ -332,11 +322,6 @@ private:
 
     bool                                    _AGC;
 
-    uint16_t                          _playWarning;
-    uint16_t                          _playError;
-    uint16_t                          _recWarning;
-    uint16_t                          _recError;
-
     uint16_t                          _playBufDelay;
 
     uint16_t                          _newMicLevel;