MediaStream: Adding VideoTrackRecorder class and unittests

content/renderer/media/video_track_recorder.h

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_RENDERER_MEDIA_VIDEO_TRACK_RECORDER_H_
+#define CONTENT_RENDERER_MEDIA_VIDEO_TRACK_RECORDER_H_
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/strings/string_piece.h"
+#include "base/threading/thread_checker.h"
+#include "content/public/renderer/media_stream_video_sink.h"
+#include "third_party/WebKit/public/platform/WebMediaStreamTrack.h"
+#include "ui/gfx/geometry/size.h"
+
+namespace media {
+class VideoFrame;
+}  // namespace media
+
+namespace content {
+
+// VideoTrackRecorder is a MediaStreamVideoSink that encodes the video frames
+// received from a Stream Video Track. The class is constructed and used on a
+// single thread, namely the main Render thread. It has an internal VpxEncoder
+// that uses a worker thread for encoding.
+class CONTENT_EXPORT VideoTrackRecorder
+    : NON_EXPORTED_BASE(public MediaStreamVideoSink) {
+ public:
+  using OnEncodedVideoCB =
+      base::Callback<void(const scoped_refptr<media::VideoFrame>& video_frame,
+                          const base::StringPiece& encoded_data,
+                          base::TimeTicks capture_timestamp,
+                          bool is_key_frame)>;
+
+  VideoTrackRecorder(const blink::WebMediaStreamTrack& track,
+                     const OnEncodedVideoCB& on_encoded_video_cb);
+  ~VideoTrackRecorder() override;
+
+ private:
+  friend class VideoTrackRecorderTest;
+
+  // Used to ping |encoder_->StartFrameEncode()| for testing.
+  void StartFrameEncodeForTesting(const scoped_refptr<media::VideoFrame>& frame,
+                                  const base::TimeTicks& capture_time);
+
+  // Used to check that we are destroyed on the same thread we were created.
+  base::ThreadChecker main_render_thread_checker_;
+
+  // We need to hold on to the Blink track to remove ourselves on dtor.
+  const blink::WebMediaStreamTrack track_;
+
+  // Forward declaration and member of an inner class to encode using VPx.
+  class VpxEncoder;
+  const scoped_refptr<VpxEncoder> encoder_;
+
+  DISALLOW_COPY_AND_ASSIGN(VideoTrackRecorder);
+};
+
+}  // namespace content
+#endif  // CONTENT_RENDERER_MEDIA_VIDEO_TRACK_RECORDER_H_