Transfer media::VideoFrame using mojo shared memory

media/mojo/common/mojo_shared_buffer_video_frame.h

 // Copyright 2016 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 MEDIA_MOJO_COMMON_MOJO_SHARED_BUFFER_VIDEO_FRAME_H_
 #define MEDIA_MOJO_COMMON_MOJO_SHARED_BUFFER_VIDEO_FRAME_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "media/base/video_frame.h"
 #include "mojo/public/cpp/system/buffer.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/size.h"
 
+namespace mojo {
+template <typename T, typename U>
+struct TypeConverter;
+template <typename T>
+class StructPtr;
+};
+
 namespace media {
 
+namespace interfaces {
+class VideoFrame;
+}
+
 // A derived class of media::VideoFrame holding a mojo::SharedBufferHandle
 // which is mapped on constructor and remains so for the lifetime of the
 // object. These frames are ref-counted.
 class MojoSharedBufferVideoFrame : public VideoFrame {
  public:
   // Creates a new I420 frame in shared memory with provided parameters
   // (coded_size() == natural_size() == visible_rect()), or returns nullptr.
   // Buffers for the frame are allocated but not initialized. The caller must
   // not make assumptions about the actual underlying sizes, but check the
   // returned VideoFrame instead.
@@ skipping 16 matching lines @@
       int32_t y_stride,
       int32_t u_stride,
       int32_t v_stride,
       base::TimeDelta timestamp);
 
   // Returns the offsets relative to the start of |shared_buffer| for the
   // |plane| specified.
   size_t PlaneOffset(size_t plane) const;
 
  private:
+  // mojo::TypeConverter added as a friend so that MojoSharedBufferVideoFrame
+  // can be transferred across a mojo connection.
+  friend struct mojo::TypeConverter<mojo::StructPtr<interfaces::VideoFrame>,
+                                    scoped_refptr<VideoFrame>>;
+
   MojoSharedBufferVideoFrame(VideoPixelFormat format,
                              const gfx::Size& coded_size,
                              const gfx::Rect& visible_rect,
                              const gfx::Size& natural_size,
                              mojo::ScopedSharedBufferHandle handle,
                              size_t mapped_size,
                              base::TimeDelta timestamp);
   ~MojoSharedBufferVideoFrame() override;
 
   // Initializes the MojoSharedBufferVideoFrame by creating a mapping onto
   // the shared memory, and then setting the strides and offsets as specified.
   bool Init(int32_t y_stride,
             int32_t u_stride,
             int32_t v_stride,
             size_t y_offset,
             size_t u_offset,
             size_t v_offset);
 
+  // Returns the mojo shared memory handle. This object continues to own the
+  // handle. Caller should call duplicate the handle if they want to keep a
+  // copy of the shared memory.
+  const mojo::SharedBufferHandle& Handle() const;
+
+  // Returns the size of the shared memory.
+  size_t MappedSize() const;
+
   mojo::ScopedSharedBufferHandle shared_buffer_handle_;
   size_t shared_buffer_size_;
   uint8_t* shared_buffer_data_;
   size_t offsets_[kMaxPlanes];
 
   DISALLOW_COPY_AND_ASSIGN(MojoSharedBufferVideoFrame);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_MOJO_COMMON_MOJO_SHARED_BUFFER_VIDEO_FRAME_H_