Clean out unused methods from VoiceEngine and VoEBase.

voice_engine/voice_engine_fixture.cc

 /*
  *  Copyright (c) 2015 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.
  */
 
 #include "voice_engine/voice_engine_fixture.h"
 #include "modules/audio_processing/include/mock_audio_processing.h"
 
 namespace webrtc {
 
 VoiceEngineFixture::VoiceEngineFixture()
     : voe_(VoiceEngine::Create()),
       base_(VoEBase::GetInterface(voe_)),
       network_(VoENetwork::GetInterface(voe_)) {
   EXPECT_NE(nullptr, base_);
   EXPECT_NE(nullptr, network_);
-  EXPECT_EQ(0, base_->RegisterVoiceEngineObserver(observer_));
   apm_ = new rtc::RefCountedObject<test::MockAudioProcessing>();
 }
 
 VoiceEngineFixture::~VoiceEngineFixture() {
   EXPECT_EQ(2, network_->Release());
-  EXPECT_EQ(0, base_->DeRegisterVoiceEngineObserver());
   EXPECT_EQ(0, base_->Terminate());
   EXPECT_EQ(1, base_->Release());
   EXPECT_TRUE(VoiceEngine::Delete(voe_));
 }
 
 }  // namespace webrtc