--- a/dom/media/MediaDecoderStateMachine.h
+++ b/dom/media/MediaDecoderStateMachine.h
@@ -369,18 +369,16 @@ protected:
 
   // Return the current time, either the audio clock if available (if the media
   // has audio, and the playback is possible), or a clock for the video.
   // Called on the state machine thread.
   // If aTimeStamp is non-null, set *aTimeStamp to the TimeStamp corresponding
   // to the returned stream time.
   media::TimeUnit GetClock(TimeStamp* aTimeStamp = nullptr) const;
 
-  void SetStartTime(int64_t aStartTimeUsecs);
-
   // Update only the state machine's current playback position (and duration,
   // if unknown).  Does not update the playback position on the decoder or
   // media element -- use UpdatePlaybackPosition for that.  Called on the state
   // machine thread, caller must hold the decoder lock.
   void UpdatePlaybackPositionInternal(const media::TimeUnit& aTime);
 
   // Update playback position and trigger next update by default time period.
   // Called on the state machine thread.