Add Opus decode wrapper to media.

webkit/media/filter_helpers.cc

Index: webkit/media/filter_helpers.cc
diff --git a/webkit/media/filter_helpers.cc b/webkit/media/filter_helpers.cc
index a21b45b371a1acf97bad12f93763518ce1cc02db..27c3154b140e6e35b5fb9b56d3581d585017cf2e 100644
--- a/webkit/media/filter_helpers.cc
+++ b/webkit/media/filter_helpers.cc
@@ -5,7 +5,9 @@
 #include "webkit/media/filter_helpers.h"
 
 #include "base/bind.h"
+#include "base/command_line.h"
 #include "media/base/filter_collection.h"
+#include "media/base/media_switches.h"
 #include "media/filters/decrypting_audio_decoder.h"
 #include "media/filters/decrypting_video_decoder.h"
 #include "media/filters/chunk_demuxer.h"
@@ -13,6 +15,7 @@
 #include "media/filters/ffmpeg_audio_decoder.h"
 #include "media/filters/ffmpeg_demuxer.h"
 #include "media/filters/ffmpeg_video_decoder.h"
+#include "media/filters/opus_audio_decoder.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebURL.h"
 #include "webkit/media/crypto/proxy_decryptor.h"
 #include "webkit/media/media_stream_client.h"
@@ -30,10 +33,18 @@ static void AddDefaultDecodersToCollection(
     const scoped_refptr<base::MessageLoopProxy>& message_loop,
     media::FilterCollection* filter_collection,
     ProxyDecryptor* proxy_decryptor) {
+
   scoped_refptr<media::FFmpegAudioDecoder> ffmpeg_audio_decoder =
       new media::FFmpegAudioDecoder(message_loop);
   filter_collection->GetAudioDecoders()->push_back(ffmpeg_audio_decoder);
 
+  const CommandLine* cmd_line = CommandLine::ForCurrentProcess();
+  if (cmd_line->HasSwitch(switches::kEnableOpusPlayback)) {
+    scoped_refptr<media::OpusAudioDecoder> opus_audio_decoder =
+        new media::OpusAudioDecoder(message_loop);
+    filter_collection->GetAudioDecoders()->push_back(opus_audio_decoder);
+  }
+
   if (proxy_decryptor) {
     scoped_refptr<media::DecryptingAudioDecoder> decrypting_audio_decoder =
         new media::DecryptingAudioDecoder(