Allow WebRtcMediaEngine to be created from any thread.

webrtc/media/base/mediaengine.h

 /*
  *  Copyright (c) 2004 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.
  */
 
@@ skipping 104 matching lines @@
   CompositeMediaEngine(webrtc::AudioDeviceModule* adm,
                        const rtc::scoped_refptr<webrtc::AudioEncoderFactory>&
                            audio_encoder_factory,
                        const rtc::scoped_refptr<webrtc::AudioDecoderFactory>&
                            audio_decoder_factory,
                        rtc::scoped_refptr<webrtc::AudioMixer> audio_mixer)
       : voice_(adm, audio_encoder_factory, audio_decoder_factory, audio_mixer) {
   }
   virtual ~CompositeMediaEngine() {}
   virtual bool Init() {
+    voice_.Init();
     video_.Init();
     return true;
   }
 
   virtual rtc::scoped_refptr<webrtc::AudioState> GetAudioState() const {
     return voice_.GetAudioState();
   }
   virtual VoiceMediaChannel* CreateChannel(webrtc::Call* call,
                                            const MediaConfig& config,
                                            const AudioOptions& options) {
@@ skipping 42 matching lines @@
   virtual ~DataEngineInterface() {}
   virtual DataMediaChannel* CreateChannel(const MediaConfig& config) = 0;
   virtual const std::vector<DataCodec>& data_codecs() = 0;
 };
 
 webrtc::RtpParameters CreateRtpParametersWithOneEncoding();
 
 }  // namespace cricket
 
 #endif  // WEBRTC_MEDIA_BASE_MEDIAENGINE_H_