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

media/base/audio_shifter.h

Index: media/base/audio_shifter.h
diff --git a/media/base/audio_shifter.h b/media/base/audio_shifter.h
index 015626922cfe59ca05e31498e42e0a24a92401c0..3429a2f197d0180e0f1ea416b3d1368bb302a4f4 100644
--- a/media/base/audio_shifter.h
+++ b/media/base/audio_shifter.h
@@ -89,6 +89,7 @@ private:
   struct AudioQueueEntry {
     AudioQueueEntry(base::TimeTicks target_playout_time_,
                     scoped_ptr<AudioBus> audio_);
+    AudioQueueEntry(const AudioQueueEntry& other);
     ~AudioQueueEntry();
     base::TimeTicks target_playout_time;
     linked_ptr<AudioBus> audio;