Monitor VideoResourceUpdater reusing destructed resource in Debug mode.

media/base/video_frame_metadata.h

 // Copyright 2015 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_METADATA_H_
 #define MEDIA_BASE_VIDEO_FRAME_METADATA_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
@@ skipping 76 matching lines @@
     // maximum sustainable utilization.  Greater than 1.0 indicates the consumer
     // is likely to stall or drop frames if the data volume is not reduced.
     //
     // Example: In a system that encodes and transmits video frames over the
     // network, this value can be used to indicate whether sufficient CPU
     // is available for encoding and/or sufficient bandwidth is available for
     // transmission over the network.  The maximum of the two utilization
     // measurements would be used as feedback.
     RESOURCE_UTILIZATION,
 
+    // This field indicates if the VideoFrame content has uploaded as

[miu, 2016/02/22 21:17:37]

This is a nice comment, but it belongs in
VideoResourceUpdater::SetPlaneResourceUniqueId() (where you set the boolan)
instead.  These details are specific to cc::VideoResourceUpdater, so they don't
belong here.

Here, you should probably just say: "Boolean used by cc::VideoResourceUpdater to
flag that this video frame's content has been cached."

[xjz, 2016/02/23 03:36:03]

Done.

+    // PlaneResource. Previously VideoResourceUpdater used VideoFrame pointer,
+    // timestamp and plane_index as the unique ID for each PlaneResource. When
+    // the original VideoFrame is destroyed and re-created a new VideoFrame
+    // with the same pointer, if the client always set the timestamp to zero,
+    // the old resource will be incorrectly reused. This field is introduced to
+    // prevent this happening.
+    RESOURCE_UPDATER_FLAG,

[miu, 2016/02/22 21:17:37]

Please move this up (to before RESOURCE_UTILIZATION) to maintain alphabetical
order.

[xjz, 2016/02/23 03:36:03]

Done.

+
     NUM_KEYS
   };
 
   VideoFrameMetadata();
   ~VideoFrameMetadata();
 
   bool HasKey(Key key) const;
 
   void Clear() { dictionary_.Clear(); }
 
@@ skipping 28 matching lines @@
   const base::BinaryValue* GetBinaryValue(Key key) const;
 
   base::DictionaryValue dictionary_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoFrameMetadata);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_VIDEO_FRAME_METADATA_H_