--- a/dom/media/MediaDecoder.cpp
+++ b/dom/media/MediaDecoder.cpp
@@ -677,28 +677,16 @@ MediaDecoder::SetStateMachineParameters(
   mOnPlaybackErrorEvent = mDecoderStateMachine->OnPlaybackErrorEvent().Connect(
     mAbstractMainThread, this, &MediaDecoder::OnPlaybackErrorEvent);
   mOnDecoderDoctorEvent = mDecoderStateMachine->OnDecoderDoctorEvent().Connect(
     mAbstractMainThread, this, &MediaDecoder::OnDecoderDoctorEvent);
   mOnMediaNotSeekable = mDecoderStateMachine->OnMediaNotSeekable().Connect(
     mAbstractMainThread, this, &MediaDecoder::OnMediaNotSeekable);
 }
 
-void
-MediaDecoder::SetMinimizePrerollUntilPlaybackStarts()
-{
-  MOZ_ASSERT(NS_IsMainThread());
-  LOG("SetMinimizePrerollUntilPlaybackStarts()");
-  mMinimizePreroll = true;
-
-  // This needs to be called before we init the state machine, otherwise it will
-  // have no effect.
-  MOZ_DIAGNOSTIC_ASSERT(!mDecoderStateMachine);
-}
-
 nsresult
 MediaDecoder::Play()
 {
   MOZ_ASSERT(NS_IsMainThread());
 
   NS_ASSERTION(mDecoderStateMachine != nullptr, "Should have state machine.");
   if (mPlaybackRate == 0) {
     return NS_OK;

--- a/dom/media/MediaDecoder.h
+++ b/dom/media/MediaDecoder.h
@@ -223,21 +223,16 @@ public:
   // Pause video playback.
   virtual void Pause();
   // Adjust the speed of the playback, optionally with pitch correction,
   virtual void SetVolume(double aVolume);
 
   virtual void SetPlaybackRate(double aPlaybackRate);
   void SetPreservesPitch(bool aPreservesPitch);
 
-  // Directs the decoder to not preroll extra samples until the media is
-  // played. This reduces the memory overhead of media elements that may
-  // not be played. Note that seeking also doesn't cause us start prerolling.
-  void SetMinimizePrerollUntilPlaybackStarts();
-
   bool GetMinimizePreroll() const { return mMinimizePreroll; }
 
   // All MediaStream-related data is protected by mReentrantMonitor.
   // We have at most one DecodedStreamData per MediaDecoder. Its stream
   // is used as the input for each ProcessedMediaStream created by calls to
   // captureStream(UntilEnded). Seeking creates a new source stream, as does
   // replaying after the input as ended. In the latter case, the new source is
   // not connected to streams created by captureStreamUntilEnded.
@@ -380,17 +375,16 @@ private:
 
   // The actual playback rate computation. The monitor must be held.
   void ComputePlaybackRate();
 
   // Returns true if we can play the entire media through without stopping
   // to buffer, given the current download and playback rates.
   virtual bool CanPlayThrough();
 
-  void SetAudioChannel(dom::AudioChannel aChannel) { mAudioChannel = aChannel; }
   dom::AudioChannel GetAudioChannel() { return mAudioChannel; }
 
   // Called from HTMLMediaElement when owner document activity changes
   virtual void SetElementVisibility(bool aIsDocumentVisible,
                                     Visibility aElementVisibility,
                                     bool aIsElementInTree);
 
   // Force override the visible state to hidden.