Move media::AudioCodec to its own source file

media/base/audio_decoder_config.h

Index: media/base/audio_decoder_config.h
diff --git a/media/base/audio_decoder_config.h b/media/base/audio_decoder_config.h
index a0e262f005d3343279ac3e5fa137549d4a203db8..0c86ba7d8006e801bdd33540a0fce0a69d7b8196 100644
--- a/media/base/audio_decoder_config.h
+++ b/media/base/audio_decoder_config.h
@@ -12,45 +12,13 @@
 
 #include "base/macros.h"
 #include "base/time/time.h"
+#include "media/base/audio_codecs.h"
 #include "media/base/channel_layout.h"
 #include "media/base/media_export.h"
 #include "media/base/sample_format.h"
 
 namespace media {
 
-enum AudioCodec {
-  // These values are histogrammed over time; do not change their ordinal
-  // values.  When deleting a codec replace it with a dummy value; when adding a
-  // codec, do so at the bottom before kAudioCodecMax, and update the value of
-  // kAudioCodecMax to equal the new codec.
-  kUnknownAudioCodec = 0,
-  kCodecAAC = 1,
-  kCodecMP3 = 2,
-  kCodecPCM = 3,
-  kCodecVorbis = 4,
-  kCodecFLAC = 5,
-  kCodecAMR_NB = 6,
-  kCodecAMR_WB = 7,
-  kCodecPCM_MULAW = 8,
-  kCodecGSM_MS = 9,
-  kCodecPCM_S16BE = 10,
-  kCodecPCM_S24BE = 11,
-  kCodecOpus = 12,
-  kCodecEAC3 = 13,
-  kCodecPCM_ALAW = 14,
-  kCodecALAC = 15,
-  kCodecAC3 = 16,
-  // DO NOT ADD RANDOM AUDIO CODECS!
-  //
-  // The only acceptable time to add a new codec is if there is production code
-  // that uses said codec in the same CL.
-
-  // Must always be equal to the largest entry ever logged.
-  kAudioCodecMax = kCodecAC3,
-};
-
-std::string MEDIA_EXPORT GetCodecName(AudioCodec codec);
-
 // TODO(dalecurtis): FFmpeg API uses |bytes_per_channel| instead of
 // |bits_per_channel|, we should switch over since bits are generally confusing
 // to work with.