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

media/filters/audio_file_reader.cc

Index: media/filters/audio_file_reader.cc
diff --git a/media/filters/audio_file_reader.cc b/media/filters/audio_file_reader.cc
index eef20fc318493399e4c162dff34f15d4e3846352..40165c4b546c8f6b0ac089a3d7f148ac846c4dcf 100644
--- a/media/filters/audio_file_reader.cc
+++ b/media/filters/audio_file_reader.cc
@@ -134,7 +134,7 @@ int AudioFileReader::Read(AudioBus* audio_bus) {
   size_t bytes_per_sample = av_get_bytes_per_sample(codec_context_->sample_fmt);
 
   // Holds decoded audio.
-  scoped_ptr<AVFrame, ScopedPtrAVFreeFrame> av_frame(av_frame_alloc());
+  std::unique_ptr<AVFrame, ScopedPtrAVFreeFrame> av_frame(av_frame_alloc());
 
   // Read until we hit EOF or we've read the requested number of frames.
   AVPacket packet;