media: Add out-of-line copy ctors for complex classes.

media/formats/webm/tracks_builder.h

 // Copyright 2014 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_FORMATS_WEBM_TRACKS_BUILDER_H_
 #define MEDIA_FORMATS_WEBM_TRACKS_BUILDER_H_
 
 #include <stdint.h>
 
 #include <list>
@@ skipping 65 matching lines @@
           uint64_t track_uid,
           const std::string& codec_id,
           const std::string& name,
           const std::string& language,
           int default_duration,
           int video_pixel_width,
           int video_pixel_height,
           int audio_channels,
           double audio_sampling_frequency,
           bool allow_invalid_values);
+    Track(const Track& other);
 
     int GetSize() const;
     void Write(uint8_t** buf, int* buf_size) const;
 
    private:
     int GetPayloadSize() const;
     int GetVideoPayloadSize() const;
     int GetAudioPayloadSize() const;
 
     int track_num_;
@@ skipping 12 matching lines @@
   typedef std::list<Track> TrackList;
   TrackList tracks_;
   bool allow_invalid_values_;
 
   DISALLOW_COPY_AND_ASSIGN(TracksBuilder);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FORMATS_WEBM_TRACKS_BUILDER_H_