Convert //media/cast from scoped_ptr to std::unique_ptr

media/cast/test/utility/audio_utility.h

Index: media/cast/test/utility/audio_utility.h
diff --git a/media/cast/test/utility/audio_utility.h b/media/cast/test/utility/audio_utility.h
index d1a4ca0569c41eb7d7ee2dbd354b56816d9532e2..027e0fb31aba61e9cfbf5840b844d8a70a7d504c 100644
--- a/media/cast/test/utility/audio_utility.h
+++ b/media/cast/test/utility/audio_utility.h
@@ -34,7 +34,7 @@ class TestAudioBusFactory {
 
   // Creates a new AudioBus of the given |duration|, filled with the next batch
   // of sine wave samples.
-  scoped_ptr<AudioBus> NextAudioBus(const base::TimeDelta& duration);
+  std::unique_ptr<AudioBus> NextAudioBus(const base::TimeDelta& duration);
 
   // A reasonable test tone.
   static const int kMiddleANoteFreq = 440;