Update native plugin dll for turn servers and video.

webrtc/examples/unityplugin/video_observer.h

+/*
+ *  Copyright (c) 2017 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.
+ */
+
+#ifndef WEBRTC_EXAMPLES_UNITYPLUGIN_VIDEO_OBSERVER_H_
+#define WEBRTC_EXAMPLES_UNITYPLUGIN_VIDEO_OBSERVER_H_
+
+#include <mutex>
+
+#include "webrtc/api/mediastreaminterface.h"
+#include "webrtc/examples/unityplugin/unity_plugin_apis.h"
+#include "webrtc/media/base/videosinkinterface.h"
+
+class VideoObserver : public rtc::VideoSinkInterface<webrtc::VideoFrame> {
+ public:
+  VideoObserver() {}
+  ~VideoObserver() {}
+  void SetVideoCallback(I420FRAMEREADY_CALLBACK callback);
+
+ protected:
+  // VideoSinkInterface implementation
+  void OnFrame(const webrtc::VideoFrame& frame) override;
+
+ private:
+  I420FRAMEREADY_CALLBACK OnI420FrameReady = nullptr;
+  std::mutex mutex;
+};
+
+#endif  // WEBRTC_EXAMPLES_UNITYPLUGIN_VIDEO_OBSERVER_H_