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

modules/audio_device/android/audio_device_template.h

Index: modules/audio_device/android/audio_device_template.h
diff --git a/modules/audio_device/android/audio_device_template.h b/modules/audio_device/android/audio_device_template.h
index 8d69cb4aa7b2510d8d208e5c0d91a8c284788cdb..df9efeeb49c90e21dacf5a3f2d84d4d747da5dec 100644
--- a/modules/audio_device/android/audio_device_template.h
+++ b/modules/audio_device/android/audio_device_template.h
@@ -391,30 +391,6 @@ class AudioDeviceTemplate : public AudioDeviceGeneric {
     return 0;
   }
 
-  bool PlayoutWarning() const override {
-    return false;
-  }
-
-  bool PlayoutError() const override {
-    return false;
-  }
-
-  bool RecordingWarning() const override {
-    return false;
-  }
-
-  bool RecordingError() const override {
-    return false;
-  }
-
-  void ClearPlayoutWarning() override { LOG(INFO) << __FUNCTION__; }
-
-  void ClearPlayoutError() override { LOG(INFO) << __FUNCTION__; }
-
-  void ClearRecordingWarning() override { LOG(INFO) << __FUNCTION__; }
-
-  void ClearRecordingError() override { LOG(INFO) << __FUNCTION__; }
-
   void AttachAudioBuffer(AudioDeviceBuffer* audioBuffer) override {
     LOG(INFO) << __FUNCTION__;
     output_.AttachAudioBuffer(audioBuffer);