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

modules/audio_device/include/mock_audio_device.h

Index: modules/audio_device/include/mock_audio_device.h
diff --git a/modules/audio_device/include/mock_audio_device.h b/modules/audio_device/include/mock_audio_device.h
index f824eeb72ba707371459407fa5231ee24f15353b..87dc64cd0720ea23d0eb9cab51ba385f744fb39b 100644
--- a/modules/audio_device/include/mock_audio_device.h
+++ b/modules/audio_device/include/mock_audio_device.h
@@ -21,18 +21,12 @@ namespace test {
 
 class MockAudioDeviceModule : public AudioDeviceModule {
  public:
-  // Module.
-  MOCK_METHOD0(TimeUntilNextProcess, int64_t());
-  MOCK_METHOD0(Process, void());
-  MOCK_METHOD1(ProcessThreadAttached, void(ProcessThread*));
-  // RefCountedModule.
+  // RefCounted
   MOCK_CONST_METHOD0(AddRef, int32_t());
   MOCK_CONST_METHOD0(Release, int32_t());
   // AudioDeviceModule.
   MOCK_CONST_METHOD1(ActiveAudioLayer, int32_t(AudioLayer* audioLayer));
   MOCK_CONST_METHOD0(LastError, ErrorCode());
-  MOCK_METHOD1(RegisterEventObserver,
-               int32_t(AudioDeviceObserver* eventCallback));
   MOCK_METHOD1(RegisterAudioCallback, int32_t(AudioTransport* audioCallback));
   MOCK_METHOD0(Init, int32_t());
   MOCK_METHOD0(Terminate, int32_t());