Add Opus decode wrapper to media.

net/base/mime_util.cc

Index: net/base/mime_util.cc
diff --git a/net/base/mime_util.cc b/net/base/mime_util.cc
index f7240f286c8bd85d19190f50195f756da9aa1d6f..262b400e327270a6211be50fa9acc695e33bd960 100644
--- a/net/base/mime_util.cc
+++ b/net/base/mime_util.cc
@@ -308,6 +308,7 @@ static const char* const common_media_codecs[] = {
   "theora",
 #endif
   "vorbis",
+  "opus",
   "vp8",
   "1"  // WAVE_FORMAT_PCM.
 };
@@ -421,8 +422,8 @@ struct MediaFormatStrict {
 };
 
 static const MediaFormatStrict format_codec_mappings[] = {
-  { "video/webm", "vorbis,vp8,vp8.0" },
-  { "audio/webm", "vorbis" },
+  { "video/webm", "vorbis,opus,vp8,vp8.0" },
+  { "audio/webm", "vorbis,opus" },
   { "audio/wav", "1" }
 };
 
@@ -812,6 +813,7 @@ static const char* const kStandardAudioTypes[] = {
   "audio/mpeg3",
   "audio/ogg",
   "audio/vorbis",
+  "audio/opus",
   "audio/wav",
   "audio/webm",
   "audio/x-m4a",