Move VideoDestinationHandler processing to the IO-thread.

content/renderer/media/webrtc/video_destination_handler.h

 // Copyright (c) 2013 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_WEBRTC_VIDEO_DESTINATION_HANDLER_H_
 #define CONTENT_RENDERER_MEDIA_WEBRTC_VIDEO_DESTINATION_HANDLER_H_
 
 #include <string>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/memory/weak_ptr.h"
 #include "content/common/content_export.h"
 #include "content/renderer/media/media_stream_video_source.h"
 #include "media/base/video_frame_pool.h"
 
 namespace content {
 
-class PeerConnectionDependencyFactory;
 class MediaStreamRegistryInterface;
 class PPB_ImageData_Impl;
 
-// Interface used by the effects pepper plugin to output the processed frame
-// to the video track.
-class CONTENT_EXPORT FrameWriterInterface {
+// VideoDestinationHandler is a glue class between the content MediaStream and
+// the effects pepper plugin host.
+class CONTENT_EXPORT VideoDestinationHandler {
  public:
-  // The ownership of the |image_data| deosn't transfer. So the implementation
-  // of this interface should make a copy of the |image_data| before return.
-  virtual void PutFrame(PPB_ImageData_Impl* image_data,
-                        int64 time_stamp_ns) = 0;
-  virtual ~FrameWriterInterface() {}
+  // FrameWriterCallback is used to forward frames from the pepper host.
+  // It must be invoked on the main render thread.
+  typedef base::Callback<
+      void(const scoped_refptr<PPB_ImageData_Impl>& frame,
+           int64 time_stamp_ns)> FrameWriterCallback;
+
+  // Instantiates and adds a new video track to the MediaStream specified by
+  // |url|. Returns a handler for delivering frames to the new video track as
+  // |frame_writer|.
+  // If |registry| is NULL the global blink::WebMediaStreamRegistry will be
+  // used to look up the media stream.
+  // Returns true on success and false on failure.
+  static bool Open(MediaStreamRegistryInterface* registry,
+                   const std::string& url,
+                   FrameWriterCallback* frame_writer);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(VideoDestinationHandler);
 };
 
 // PpFrameWriter implements MediaStreamVideoSource and can therefore provide
-// video frames to MediaStreamVideoTracks. It also implements
-// FrameWriterInterface, which will be used by the effects pepper plugin to
-// inject the processed frame.
+// video frames to MediaStreamVideoTracks.
 class CONTENT_EXPORT PpFrameWriter
-    : NON_EXPORTED_BASE(public MediaStreamVideoSource),
-      public FrameWriterInterface,
-      NON_EXPORTED_BASE(public base::SupportsWeakPtr<PpFrameWriter>) {
+    : NON_EXPORTED_BASE(public MediaStreamVideoSource) {
  public:
   PpFrameWriter();
   virtual ~PpFrameWriter();
 
-  // FrameWriterInterface implementation.
-  // This method will be called by the Pepper host from render thread.
-  virtual void PutFrame(PPB_ImageData_Impl* image_data,
-                        int64 time_stamp_ns) override;
+  // Returns a callback that can be used for delivering frames to this
+  // MediaStreamSource implementation.
+  VideoDestinationHandler::FrameWriterCallback GetFrameWriterCallback();
+
  protected:
   // MediaStreamVideoSource implementation.
   virtual void GetCurrentSupportedFormats(
       int max_requested_width,
       int max_requested_height,
       double max_requested_frame_rate,
       const VideoCaptureDeviceFormatsCB& callback) override;
   virtual void StartSourceImpl(
       const media::VideoCaptureFormat& format,
       const VideoCaptureDeliverFrameCB& frame_callback) override;
   virtual void StopSourceImpl() override;
 
  private:
-  media::VideoFramePool frame_pool_;
-
   class FrameWriterDelegate;
   scoped_refptr<FrameWriterDelegate> delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(PpFrameWriter);
 };
 
-// VideoDestinationHandler is a glue class between the content MediaStream and
-// the effects pepper plugin host.
-class CONTENT_EXPORT VideoDestinationHandler {
- public:
-  // Instantiates and adds a new video track to the MediaStream specified by
-  // |url|. Returns a handler for delivering frames to the new video track as
-  // |frame_writer|.
-  // If |registry| is NULL the global blink::WebMediaStreamRegistry will be
-  // used to look up the media stream.
-  // The caller of the function takes the ownership of |frame_writer|.
-  // Returns true on success and false on failure.
-  static bool Open(MediaStreamRegistryInterface* registry,
-                   const std::string& url,
-                   FrameWriterInterface** frame_writer);
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(VideoDestinationHandler);
-};
-
 }  // namespace content
 
-#endif  // CONTENT_RENDERER_MEDIA_VIDEO_DESTINATION_HANDLER_H_
+#endif  // CONTENT_RENDERER_MEDIA_WEBRTC_VIDEO_DESTINATION_HANDLER_H_