Refactor MediaStreamTrack video onmute event.

content/renderer/media/media_stream_track.cc

Index: content/renderer/media/media_stream_track.cc
diff --git a/content/renderer/media/media_stream_track.cc b/content/renderer/media/media_stream_track.cc
index 6ba46fcf53cabefc0abae101e9caf193e59744a0..458748e2f9c24d384c6b165f5da75a6a68c51867 100644
--- a/content/renderer/media/media_stream_track.cc
+++ b/content/renderer/media/media_stream_track.cc
@@ -20,7 +20,7 @@ MediaStreamTrack* MediaStreamTrack::GetTrack(
 MediaStreamTrack::MediaStreamTrack(
     const scoped_refptr<webrtc::MediaStreamTrackInterface>& track,
     bool is_local_track)
-    : track_(track), muted_state_(false), is_local_track_(is_local_track) {
+    : track_(track), is_local_track_(is_local_track) {
 }
 
 MediaStreamTrack::~MediaStreamTrack() {
@@ -32,16 +32,6 @@ void MediaStreamTrack::SetEnabled(bool enabled) {
     track_->set_enabled(enabled);
 }
 
-void MediaStreamTrack::SetMutedState(bool muted_state) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  muted_state_ = muted_state;
-}
-
-bool MediaStreamTrack::GetMutedState(void) const {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  return muted_state_;
-}
-
 void MediaStreamTrack::Stop() {
   DCHECK(thread_checker_.CalledOnValidThread());
   // Stop means that a track should be stopped permanently. But