Remove the unused NullMediaEngine (and NullVoiceEngine+NullVideoEngine).

talk/media/base/mediaengine.h

 /*
  * libjingle
  * Copyright 2004 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *  1. Redistributions of source code must retain the above copyright notice,
  *     this list of conditions and the following disclaimer.
  *  2. Redistributions in binary form must reproduce the above copyright notice,
@@ skipping 213 matching lines @@
     return voice_.StartRtcEventLog(file);
   }
 
   virtual void StopRtcEventLog() { voice_.StopRtcEventLog(); }
 
  protected:
   VOICE voice_;
   VIDEO video_;
 };
 
-// NullVoiceEngine can be used with CompositeMediaEngine in the case where only
-// a video engine is desired.
-class NullVoiceEngine {
- public:
-  bool Init(rtc::Thread* worker_thread) { return true; }
-  void Terminate() {}
-  // If you need this to return an actual channel, use FakeMediaEngine instead.
-  VoiceMediaChannel* CreateChannel(const AudioOptions& options) {
-    return nullptr;
-  }
-  AudioOptions GetOptions() const { return AudioOptions(); }
-  bool SetOptions(const AudioOptions& options) { return true; }
-  bool SetDevices(const Device* in_device, const Device* out_device) {
-    return true;
-  }
-  bool GetOutputVolume(int* level) {
-    *level = 0;
-    return true;
-  }
-  bool SetOutputVolume(int level) { return true; }
-  int GetInputLevel() { return 0; }
-  const std::vector<AudioCodec>& codecs() { return codecs_; }
-  const std::vector<RtpHeaderExtension>& rtp_header_extensions() {
-    return rtp_header_extensions_;
-  }
-  bool StartAecDump(rtc::PlatformFile file) { return false; }
-  bool StartRtcEventLog(rtc::PlatformFile file) { return false; }
-  void StopRtcEventLog() {}
-
- private:
-  std::vector<AudioCodec> codecs_;
-  std::vector<RtpHeaderExtension> rtp_header_extensions_;
-};
-
-// NullVideoEngine can be used with CompositeMediaEngine in the case where only
-// a voice engine is desired.
-class NullVideoEngine {
- public:
-  bool Init(rtc::Thread* worker_thread) { return true; }
-  void Terminate() {}
-  // If you need this to return an actual channel, use FakeMediaEngine instead.
-  VideoMediaChannel* CreateChannel(
-      const VideoOptions& options,
-      VoiceMediaChannel* voice_media_channel) {
-    return NULL;
-  }
-  bool SetOptions(const VideoOptions& options) { return true; }
-  bool SetDefaultEncoderConfig(const VideoEncoderConfig& config) {
-    return true;
-  }
-  const std::vector<VideoCodec>& codecs() { return codecs_; }
-  const std::vector<RtpHeaderExtension>& rtp_header_extensions() {
-    return rtp_header_extensions_;
-  }
-
- private:
-  std::vector<VideoCodec> codecs_;
-  std::vector<RtpHeaderExtension> rtp_header_extensions_;
-};
-
-typedef CompositeMediaEngine<NullVoiceEngine, NullVideoEngine> NullMediaEngine;
-
 enum DataChannelType {
   DCT_NONE = 0,
   DCT_RTP = 1,
   DCT_SCTP = 2
 };
 
 class DataEngineInterface {
  public:
   virtual ~DataEngineInterface() {}
   virtual DataMediaChannel* CreateChannel(DataChannelType type) = 0;
   virtual const std::vector<DataCodec>& data_codecs() = 0;
 };
 
 }  // namespace cricket
 
 #endif  // TALK_MEDIA_BASE_MEDIAENGINE_H_