[NOT FOR REVIEW][PPAPI] Implement MediaStreamVideoTrack pepper API

ppapi/shared_impl/media_stream_track_base_shared.h

+// Copyright (c) 2014 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 PPAPI_SHARED_IMPL_MEDIA_STREAM_TRACK_BASE_SHARED_H_
+#define PPAPI_SHARED_IMPL_MEDIA_STREAM_TRACK_BASE_SHARED_H_
+
+#include <deque>
+#include <vector>
+
+#include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/shared_memory.h"
+#include "ppapi/shared_impl/media_stream_frame.h"
+#include "ppapi/shared_impl/ppapi_shared_export.h"
+
+namespace ppapi {
+
+class PPAPI_SHARED_EXPORT MediaStreamTrackBaseShared {
+ protected:
+  MediaStreamTrackBaseShared();
+
+  virtual ~MediaStreamTrackBaseShared();
+
+  int32_t number_of_frames() const { return number_of_frames_; }
+
+  int32_t frame_size() const { return frame_size_; }
+
+  // Initializes shared memory for frames transmission.
+  bool SetFrames(int32_t number_of_frames,
+                 int32_t frame_size,
+                 scoped_ptr<base::SharedMemory> shm);
+
+  // Dequeues a frame from |frame_queue_|.
+  int32_t DequeueFrame();
+
+  // Puts a frame into |frame_queue_|.
+  void EnqueueFrame(int32_t index);
+
+  // Gets a frame address for the given index.
+  MediaStreamFrame* GetFramePointer(int32_t index);
+
+  // Subclass should implement this method to get notification when a new frame
+  // is enqueued.
+  virtual void OnNewFrameEnqueued();
+
+ private:
+  // A queue of incoming frame indexes.
+  // For the input side, they are empty frames which will be filled with data
+  // and sent to the output side.
+  // For the output side, they are received frames waiting for consuming.
+  std::deque<int32_t> frame_queue_;
+
+  // A vector of frame pointers. It is used for index to pointer converting.
+  std::vector<MediaStreamFrame*> frames_;
+
+  // The frame size in bytes.
+  int32_t frame_size_;
+
+  // The number of frames in the shared memory.
+  int32_t number_of_frames_;
+
+  // A memory block shared between renderer and plugin processes.
+  scoped_ptr<base::SharedMemory> shm_;
+
+  DISALLOW_COPY_AND_ASSIGN(MediaStreamTrackBaseShared);
+};
+
+}  // namespace ppapi
+
+#endif  // PPAPI_SHAERD_IMPL_MEDIA_STREAM_TRACK_BASE_SHARED_H_