Move media::AudioCodec to its own source file

media/filters/ffmpeg_audio_decoder.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/filters/ffmpeg_audio_decoder.h"
 
 #include <stdint.h>
 
 #include "base/callback_helpers.h"
 #include "base/single_thread_task_runner.h"
@@ skipping 110 matching lines @@
 
   // Now create an AVBufferRef for the data just allocated. It will own the
   // reference to the AudioBuffer object.
   void* opaque = NULL;
   buffer.swap(reinterpret_cast<AudioBuffer**>(&opaque));
   frame->buf[0] = av_buffer_create(
       frame->data[0], buffer_size_in_bytes, ReleaseAudioBufferImpl, opaque, 0);
   return 0;
 }
 
+// static
+bool FFmpegAudioDecoder::IsCodecSupported(AudioCodec codec,
+                                          SampleFormat sample_format) {
+  FFmpegGlue::InitializeFFmpeg();
+  return avcodec_find_decoder(AudioCodecToCodecID(codec, sample_format)) !=
+         nullptr;
+}
+
 FFmpegAudioDecoder::FFmpegAudioDecoder(
     const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
     const scoped_refptr<MediaLog>& media_log)
     : task_runner_(task_runner),
       state_(kUninitialized),
       av_sample_format_(0),
       media_log_(media_log) {
 }
 
 FFmpegAudioDecoder::~FFmpegAudioDecoder() {
@@ skipping 246 matching lines @@
   return true;
 }
 
 void FFmpegAudioDecoder::ResetTimestampState() {
   discard_helper_.reset(new AudioDiscardHelper(config_.samples_per_second(),
                                                config_.codec_delay()));
   discard_helper_->Reset(config_.codec_delay());
 }
 
 }  // namespace media