Refactor VideoTrackRecorder into smaller classes

content/renderer/media_recorder/h264_encoder.h

+// Copyright 2017 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_RECORDER_H264_ENCODER_H_
+#define CONTENT_RENDERER_MEDIA_RECORDER_H264_ENCODER_H_
+
+#include "content/public/common/features.h"
+
+#if !BUILDFLAG(RTC_USE_H264)
+#error RTC_USE_H264 should be defined.
+#endif  // #if BUILDFLAG(RTC_USE_H264)
+
+#include "base/time/time.h"
+#include "content/renderer/media_recorder/video_track_recorder.h"
+#include "third_party/openh264/src/codec/api/svc/codec_api.h"
+
+namespace content {
+
+// Class encapsulating all openh264 interactions for H264 encoding.
+class H264Encoder final : public VideoTrackRecorder::Encoder {
+ public:
+  struct ISVCEncoderDeleter {
+    void operator()(ISVCEncoder* codec);
+  };
+  typedef std::unique_ptr<ISVCEncoder, ISVCEncoderDeleter> ScopedISVCEncoderPtr;
+
+  static void ShutdownEncoder(std::unique_ptr<base::Thread> encoding_thread,
+                              ScopedISVCEncoderPtr encoder);
+
+  H264Encoder(
+      const VideoTrackRecorder::OnEncodedVideoCB& on_encoded_video_callback,
+      int32_t bits_per_second);
+
+ private:
+  // VideoTrackRecorder::Encoder implementation.
+  ~H264Encoder() override;
+  void EncodeOnEncodingTaskRunner(scoped_refptr<media::VideoFrame> frame,
+                                  base::TimeTicks capture_timestamp) override;
+
+  void ConfigureEncoderOnEncodingTaskRunner(const gfx::Size& size);
+
+  // |openh264_encoder_| is a special scoped pointer to guarantee proper
+  // destruction, also when reconfiguring due to parameters change. Only used on
+  // VideoTrackRecorder::Encoder::encoding_thread_.
+  gfx::Size configured_size_;
+  ScopedISVCEncoderPtr openh264_encoder_;
+
+  // The |VideoFrame::timestamp()| of the first received frame. Only used on
+  // VideoTrackRecorder::Encoder::encoding_thread_.
+  base::TimeTicks first_frame_timestamp_;
+
+  DISALLOW_COPY_AND_ASSIGN(H264Encoder);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_MEDIA_RECORDER_H264_ENCODER_H_