Move VoiceEngineObserver into AudioSendStream so that we detect typing noises and return properly i…

webrtc/test/fake_voice_engine.h

Index: webrtc/test/fake_voice_engine.h
diff --git a/webrtc/test/fake_voice_engine.h b/webrtc/test/fake_voice_engine.h
index 8f08929720cacf35c96b7c7c63348e98abe1442e..42f89d0fe2c27bd32ad3f3c0e722d544a8f28a3e 100644
--- a/webrtc/test/fake_voice_engine.h
+++ b/webrtc/test/fake_voice_engine.h
@@ -135,9 +135,9 @@ class FakeVoiceEngine final : public VoiceEngineImpl {
 
   // VoEBase
   int RegisterVoiceEngineObserver(VoiceEngineObserver& observer) override {
-    return -1;
+    return 0;
   }
-  int DeRegisterVoiceEngineObserver() override { return -1; }
+  int DeRegisterVoiceEngineObserver() override { return 0; }
   int Init(AudioDeviceModule* external_adm = NULL,
            AudioProcessing* audioproc = NULL) override { return -1; }
   AudioProcessing* audio_processing() override { return nullptr; }