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

pc/test/fakeaudiocapturemodule.h

Index: pc/test/fakeaudiocapturemodule.h
diff --git a/pc/test/fakeaudiocapturemodule.h b/pc/test/fakeaudiocapturemodule.h
index b73b6427693e4ca72eec180cbaa0c1f10cef72a2..fd2290b3da6d59e1d6bd04a16377321973e79a9f 100644
--- a/pc/test/fakeaudiocapturemodule.h
+++ b/pc/test/fakeaudiocapturemodule.h
@@ -52,18 +52,9 @@ class FakeAudioCaptureModule
   // pulled frame was generated/pushed from a FakeAudioCaptureModule.
   int frames_received() const;
 
-  // Following functions are inherited from webrtc::AudioDeviceModule.
-  // Only functions called by PeerConnection are implemented, the rest do
-  // nothing and return success. If a function is not expected to be called by
-  // PeerConnection an assertion is triggered if it is in fact called.
-  int64_t TimeUntilNextProcess() override;
-  void Process() override;
-
   int32_t ActiveAudioLayer(AudioLayer* audio_layer) const override;
 
   ErrorCode LastError() const override;
-  int32_t RegisterEventObserver(
-      webrtc::AudioDeviceObserver* event_callback) override;
 
   // Note: Calling this method from a callback may result in deadlock.
   int32_t RegisterAudioCallback(
@@ -210,10 +201,6 @@ class FakeAudioCaptureModule
   // Pushes frames to the registered webrtc::AudioTransport.
   void SendFrameP();
 
-  // The time in milliseconds when Process() was last called or 0 if no call
-  // has been made.
-  int64_t last_process_time_ms_;
-
   // Callback for playout and recording.
   webrtc::AudioTransport* audio_callback_;