Add mailbox-based Mojo VideoFrame variant.

media/base/video_frame.h

 // Copyright (c) 2012 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_BASE_VIDEO_FRAME_H_
 #define MEDIA_BASE_VIDEO_FRAME_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 337 matching lines @@
 #endif
 
   void AddSharedMemoryHandle(base::SharedMemoryHandle handle);
 
 #if defined(OS_MACOSX)
   // Returns the backing CVPixelBuffer, if present.
   // TODO(mcasas): Rename to CvPixelBuffer() to comply with Style Guide.
   CVPixelBufferRef cv_pixel_buffer() const;
 #endif
 
+  // Sets the mailbox release callback.
+  // The callback may be run from ANY THREAD, and so it is up to the client to
+  // ensure thread safety.
+  void SetReleaseMailboxCB(const ReleaseMailboxCB& release_mailbox_cb);

[sandersd (OOO until July 31), 2017/01/19 19:40:48]

Option B is that the VideoFrame converter needs to become aware of this
callback, and therefore cannot be a standard Mojo converter.

[xhwang, 2017/01/25 18:25:09]

This is fine IMHO. VideoFrame is already a mix of everything :(

[sandersd (OOO until July 31), 2017/01/26 23:49:05]

Acknowledged.

+
   // Adds a callback to be run when the VideoFrame is about to be destroyed.
   // The callback may be run from ANY THREAD, and so it is up to the client to
   // ensure thread safety.  Although read-only access to the members of this
   // VideoFrame is permitted while the callback executes (including
   // VideoFrameMetadata), clients should not assume the data pointers are
   // valid.
   void AddDestructionObserver(const base::Closure& callback);
 
   // Returns a dictionary of optional metadata.  This contains information
   // associated with the frame that downstream clients might use for frame-level
@@ skipping 174 matching lines @@
   const int unique_id_;
 
   gfx::ColorSpace color_space_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(VideoFrame);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_VIDEO_FRAME_H_