WebmMuxer-MediaRecorderHandler: thread hopping and data ownership

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
 // with its own threading subtleties, see the implementation file. This mirrors
 // the other MediaStreamVideo* classes that are constructed/configured on Main
 // Render thread but that pass frames on Render IO thread.
 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,
+                          scoped_ptr<std::string> encoded_data,
                           base::TimeTicks capture_timestamp,
                           bool is_key_frame)>;
 
   VideoTrackRecorder(const blink::WebMediaStreamTrack& track,
                      const OnEncodedVideoCB& on_encoded_video_cb);
   ~VideoTrackRecorder() override;
 
   void OnVideoFrameForTesting(const scoped_refptr<media::VideoFrame>& frame,
                               base::TimeTicks capture_time);
 
  private:
   friend class VideoTrackRecorderTest;
 
   // 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.
   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_