WebmMuxer-MediaRecorderHandler: thread hopping and data ownership

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
index a97843bba757f81ed06da8c691718b4bf3962300..50d688ae8595432f17a089bdd6eb9e7fc4ea2a69 100644
--- a/content/renderer/media/media_recorder_handler.h
+++ b/content/renderer/media/media_recorder_handler.h
@@ -8,7 +8,6 @@
 #include "base/compiler_specific.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/WebMediaRecorderHandler.h"
@@ -28,22 +27,23 @@ namespace content {
 
 class VideoTrackRecorder;
 
-// MediaRecorderHandler orchestrates the creation, lifetime mgmt and mapping
-// between:
+// MediaRecorderHandler orchestrates the creation, lifetime management 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.
+// i.e. the Main Render thread. (Note that a BindToCurrentLoop is used to
+// guarantee this, since VideoTrackRecorder sends back frames on IO thread.)
+// TODO(mcasas): http://crbug.com/528519 Implement audio recording.
 class CONTENT_EXPORT MediaRecorderHandler final
     : public NON_EXPORTED_BASE(blink::WebMediaRecorderHandler) {
  public:
   MediaRecorderHandler();
   ~MediaRecorderHandler() override;
 
-  // See above, these methods should override blink::WebMediaRecorderHandler.
+  // blink::WebMediaRecorderHandler.
   bool canSupportMimeType(const blink::WebString& mimeType) override;
   bool initialize(blink::WebMediaRecorderHandlerClient* client,
                   const blink::WebMediaStream& media_stream,
@@ -57,7 +57,11 @@ class CONTENT_EXPORT MediaRecorderHandler final
  private:
   friend class MediaRecorderHandlerTest;
 
-  void WriteData(const base::StringPiece& data);
+  void OnEncodedVideo(const scoped_refptr<media::VideoFrame>& video_frame,
+                      scoped_ptr<std::string> encoded_data,
+                      base::TimeTicks timestamp,
+                      bool is_key_frame);
+  void WriteData(scoped_ptr<std::string> data);

[miu, 2015/09/22 04:11:08]

FWICT, there was no need to change the WriteData() method.  See comment in
webm_muxer.cc.

[mcasas, 2015/09/22 16:58:40]

Acknowledged.

 
   void OnVideoFrameForTesting(const scoped_refptr<media::VideoFrame>& frame,
                               const base::TimeTicks& timestamp);