--- a/dom/media/MediaDecoderStateMachine.cpp
+++ b/dom/media/MediaDecoderStateMachine.cpp
@@ -691,32 +691,16 @@ MediaDecoderStateMachine::Push(MediaData
   } else {
     // TODO: Handle MediaRawData, determine which queue should be pushed.
   }
   UpdateNextFrameStatus();
   DispatchDecodeTasksIfNeeded();
 }
 
 void
-MediaDecoderStateMachine::PushFront(MediaData* aSample, MediaData::Type aSampleType)
-{
-  MOZ_ASSERT(OnTaskQueue());
-  MOZ_ASSERT(aSample);
-  if (aSample->mType == MediaData::AUDIO_DATA) {
-    AudioQueue().PushFront(aSample);
-  } else if (aSample->mType == MediaData::VIDEO_DATA) {
-    aSample->As<VideoData>()->mFrameID = ++mCurrentFrameID;
-    VideoQueue().PushFront(aSample);
-  } else {
-    // TODO: Handle MediaRawData, determine which queue should be pushed.
-  }
-  UpdateNextFrameStatus();
-}
-
-void
 MediaDecoderStateMachine::CheckIsAudible(const MediaData* aSample)
 {
   MOZ_ASSERT(OnTaskQueue());
   MOZ_ASSERT(aSample->mType == MediaData::AUDIO_DATA);
 
   const AudioData* data = aSample->As<AudioData>();
   bool isAudible = data->IsAudible();
   if (isAudible && !mIsAudioDataAudible) {

--- a/dom/media/MediaDecoderStateMachine.h
+++ b/dom/media/MediaDecoderStateMachine.h
@@ -387,17 +387,16 @@ protected:
   void SetState(State aState);
 
   void BufferedRangeUpdated();
 
   // Inserts MediaData* samples into their respective MediaQueues.
   // aSample must not be null.
 
   void Push(MediaData* aSample, MediaData::Type aSampleType);
-  void PushFront(MediaData* aSample, MediaData::Type aSampleType);
 
   void OnAudioPopped(const RefPtr<MediaData>& aSample);
   void OnVideoPopped(const RefPtr<MediaData>& aSample);
 
   void CheckIsAudible(const MediaData* aSample);
   void VolumeChanged();
   void LogicalPlaybackRateChanged();
   void PreservesPitchChanged();