Preliminary change for new rtc rendering algorithm

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 <vector>
 
 #include "base/callback.h"
@@ skipping 346 matching lines @@
 
   // Returns a dictionary of optional metadata.  This contains information
   // associated with the frame that downstream clients might use for frame-level
   // logging, quality/performance optimizations, signaling, etc.
   //
   // TODO(miu): Move some of the "extra" members of VideoFrame (below) into
   // here as a later clean-up step.
   const VideoFrameMetadata* metadata() const { return &metadata_; }
   VideoFrameMetadata* metadata() { return &metadata_; }
 
+  // The time span between the current frame and the first frame of the stream.
+  // This is the media timestamp, and not the reference time.
+  // See VideoFrameMetadata::REFERENCE_TIME for details.
   base::TimeDelta timestamp() const { return timestamp_; }
   void set_timestamp(base::TimeDelta timestamp) {
     timestamp_ = timestamp;
   }
 
   // It uses |client| to insert a new sync point and potentially waits on a
   // older sync point. The final sync point will be used to release this
   // VideoFrame.
   // This method is thread safe. Both blink and compositor threads can call it.
   void UpdateReleaseSyncPoint(SyncPointClient* client);
@@ skipping 99 matching lines @@
   uint32 release_sync_point_;
 
   VideoFrameMetadata metadata_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(VideoFrame);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_VIDEO_FRAME_H_