Replace scoped_ptr with std::unique_ptr in //media/base.

media/base/audio_buffer_converter.cc

Index: media/base/audio_buffer_converter.cc
diff --git a/media/base/audio_buffer_converter.cc b/media/base/audio_buffer_converter.cc
index 5fd92df15a4974e059c9b5cd2a56a47fccc542ce..d8ea29ee6529c6767bc1b268dc51e2da3d55d913 100644
--- a/media/base/audio_buffer_converter.cc
+++ b/media/base/audio_buffer_converter.cc
@@ -193,7 +193,7 @@ void AudioBufferConverter::ConvertIfPossible() {
                                 output_params_.channels(),
                                 output_params_.sample_rate(),
                                 request_frames);
-  scoped_ptr<AudioBus> output_bus =
+  std::unique_ptr<AudioBus> output_bus =
       AudioBus::CreateWrapper(output_buffer->channel_count());
 
   int frames_remaining = request_frames;