Add struct traits for base::Value.

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 <memory>
 #include <string>
 
@@ skipping 138 matching lines @@
   bool GetTimeDelta(Key key, base::TimeDelta* value) const WARN_UNUSED_RESULT;
   bool GetTimeTicks(Key key, base::TimeTicks* value) const WARN_UNUSED_RESULT;
 
   // Returns null if |key| was not present.
   const base::Value* GetValue(Key key) const WARN_UNUSED_RESULT;
 
   // Convenience method that returns true if |key| exists and is set to true.
   bool IsTrue(Key key) const WARN_UNUSED_RESULT;
 
   // For serialization.
-  void MergeInternalValuesInto(base::DictionaryValue* out) const;
+  std::unique_ptr<base::DictionaryValue> CopyInternalValues() const;
   void MergeInternalValuesFrom(const base::DictionaryValue& in);
 
   // Merges internal values from |metadata_source|.
   void MergeMetadataFrom(const VideoFrameMetadata* metadata_source);
 
  private:
   const base::BinaryValue* GetBinaryValue(Key key) const;
 
   base::DictionaryValue dictionary_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoFrameMetadata);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_VIDEO_FRAME_METADATA_H_