Revert of MediaStream audio object graph untangling and clean-ups.

content/renderer/media/speech_recognition_audio_sink.cc

Index: content/renderer/media/speech_recognition_audio_sink.cc
diff --git a/content/renderer/media/speech_recognition_audio_sink.cc b/content/renderer/media/speech_recognition_audio_sink.cc
index 3beb5a8d6b226e8db989167bb020c25d03efc746..3789422197564d44234a7c2eeb7f1026fb22c4ef 100644
--- a/content/renderer/media/speech_recognition_audio_sink.cc
+++ b/content/renderer/media/speech_recognition_audio_sink.cc
@@ -61,8 +61,11 @@
 // static
 bool SpeechRecognitionAudioSink::IsSupportedTrack(
     const blink::WebMediaStreamTrack& track) {
+  if (track.source().getType() != blink::WebMediaStreamSource::TypeAudio)
+    return false;
+
   MediaStreamAudioSource* native_source =
-      MediaStreamAudioSource::From(track.source());
+      static_cast<MediaStreamAudioSource*>(track.source().getExtraData());
   if (!native_source)
     return false;