Roll FFmpeg for M37.

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 80f8ce60a624e66d0016224d1e0b6cd88476f8d5..b20fd8d9ce35795b7ed94e5cea8177d80f0f25f0 100644
--- a/media/filters/audio_file_reader.cc
+++ b/media/filters/audio_file_reader.cc
@@ -131,7 +131,9 @@ int AudioFileReader::Read(AudioBus* audio_bus) {
     // decoded from the packet; otherwise av_free_packet() will corrupt memory.
     AVPacket packet_temp = packet;
     do {
-      avcodec_get_frame_defaults(av_frame.get());
+      // Reset frame to default values.
+      av_frame_unref(av_frame.get());
+
       int frame_decoded = 0;
       int result = avcodec_decode_audio4(
           codec_context_, av_frame.get(), &frame_decoded, &packet_temp);