MediaRecorderHandler (video part) and unittests

content/renderer/media/media_recorder_handler.h

Index: content/renderer/media/media_recorder_handler.h
diff --git a/content/renderer/media/media_recorder_handler.h b/content/renderer/media/media_recorder_handler.h
new file mode 100644
index 0000000000000000000000000000000000000000..8b9ed28048a17ada0f39f7ef17585c1dabd6aff9
--- /dev/null
+++ b/content/renderer/media/media_recorder_handler.h
@@ -0,0 +1,89 @@
+// 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_MEDIA_RECORDER_HANDLER_H_
+#define CONTENT_RENDERER_MEDIA_MEDIA_RECORDER_HANDLER_H_
+
+#include "base/memory/scoped_vector.h"
+#include "base/memory/weak_ptr.h"
+#include "base/strings/string_piece.h"
+#include "base/threading/thread_checker.h"
+#include "content/common/content_export.h"
+#include "third_party/WebKit/public/platform/WebMediaStream.h"
+#include "third_party/WebKit/public/platform/WebString.h"
+
+namespace media {
+class VideoFrame;
+class WebmMuxer;
+}  // namespace media
+
+namespace content {
+
+class VideoTrackRecorder;
+
+// TODO(mcasas): This class should derive from WebMediaRecorderHandler as
+// defined in [1] whenever Blink http://crrev.com/1255873002 is landed, and use
+// a WebMediaRecorderHandlerClient instead of MediaRecorderHandlerClient.
+// [1] http://w3c.github.io/mediacapture-record/MediaRecorder.html#MediaRecorderAPI
+class MediaRecorderHandlerClient {
+ public:
+  virtual ~MediaRecorderHandlerClient() = default;
+
+  virtual void writeData(const char* data, size_t length, bool lastInslice) = 0;

[miu, 2015/09/02 21:28:13]

Should the name of the 3rd arg be lastInSlice (capital S) here and everywhere
else in the .h and .cc files?

[mcasas, 2015/09/04 02:16:30]

Done.

+};
+
+// MediaRecorderHandler orchestrates the creation, lifetime mgmt and mapping
+// between:
+// - MediaStreamTrack(s) providing data,
+// - {Audio,Video}TrackRecorders encoding that data,
+// - a WebmMuxer class multiplexing encoded data into a WebM container, and
+// - a single recorder |client_| receiving this contained data.
+// All methods are called on the same thread as construction and destruction,
+// i.e. the Main Render thread.
+// TODO(mcasas): Implement audio recording.
+class CONTENT_EXPORT MediaRecorderHandler final {
+ public:
+  MediaRecorderHandler();
+  ~MediaRecorderHandler();
+
+  // See above, these methods should override blink::WebMediaRecorderHandler.
+  bool canSupportMimeType(const blink::WebString& mimeType);
+  bool initialize(MediaRecorderHandlerClient* client,
+                  const blink::WebMediaStream& media_stream,
+                  const blink::WebString& mimeType);
+  bool start();
+  bool start(int timeslice);
+  void stop();
+  void pause();
+  void resume();
+
+ private:
+  friend class MediaRecorderHandlerTest;
+
+  void WriteData(const base::StringPiece& data);
+
+  void OnVideoFrameForTesting(const scoped_refptr<media::VideoFrame>& frame,
+                              const base::TimeTicks& timestamp);
+
+  // Bound to the main render thread.
+  base::ThreadChecker main_render_thread_checker_;
+
+  bool recording_;

[miu, 2015/09/02 21:28:13]

You don't need this boolean.  You could replace it with a private helper method:

  bool is_recording() const { return !!webm_muxer_; }

[mcasas, 2015/09/04 02:16:30]

Still needs to be |recording_|  == false between pause() and
resume(), and  |webm_muxer_| exists in that period of time.

[miu, 2015/09/04 21:48:52]

Acknowledged.

+  blink::WebMediaStream media_stream_;  // The MediaStream being recorded.
+
+  // |client_| is a weak pointer, and is valid for the lifetime of this object.
+  MediaRecorderHandlerClient* client_;
+
+  ScopedVector<VideoTrackRecorder> video_recorders_;
+
+  // Worker class doing the actual Webm Muxing work.
+  scoped_ptr<media::WebmMuxer> webm_muxer_;
+
+  base::WeakPtrFactory<MediaRecorderHandler> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(MediaRecorderHandler);
+};
+
+}  // namespace content
+#endif  // CONTENT_RENDERER_MEDIA_MEDIA_RECORDER_HANDLER_H_