--- a/dom/media/MediaDecoderStateMachine.h
+++ b/dom/media/MediaDecoderStateMachine.h
@@ -586,21 +586,16 @@ protected:
 
   // Performs one "cycle" of the state machine. Polls the state, and may send
   // a video frame to be displayed, and generally manages the decode. Called
   // periodically via timer to ensure the video stays in sync.
   nsresult RunStateMachine();
 
   bool IsStateMachineScheduled() const;
 
-  // Returns true if we're not playing and the decode thread has filled its
-  // decode buffers and is waiting. We can shut the decode thread down in this
-  // case as it may not be needed again.
-  bool IsPausedAndDecoderWaiting();
-
   // These return true if the respective stream's decode has not yet reached
   // the end of stream.
   bool IsAudioDecoding();
   bool IsVideoDecoding();
 
 private:
   // Resolved by the MediaSink to signal that all audio/video outstanding
   // work is complete and identify which part(a/v) of the sink is shutting down.