--- a/dom/media/MediaDecoderStateMachine.cpp
+++ b/dom/media/MediaDecoderStateMachine.cpp
@@ -67,28 +67,30 @@ using namespace mozilla::media;
 #undef DECODER_LOG
 #undef VERBOSE_LOG
 #undef SAMPLE_LOG
 #undef DECODER_WARN
 #undef DUMP_LOG
 #undef SFMT
 #undef SLOG
 #undef SWARN
+#undef SDUMP
 
 #define FMT(x, ...) "Decoder=%p " x, mDecoderID, ##__VA_ARGS__
 #define DECODER_LOG(...) MOZ_LOG(gMediaDecoderLog, LogLevel::Debug,   (FMT(__VA_ARGS__)))
 #define VERBOSE_LOG(...) MOZ_LOG(gMediaDecoderLog, LogLevel::Verbose, (FMT(__VA_ARGS__)))
 #define SAMPLE_LOG(...)  MOZ_LOG(gMediaSampleLog,  LogLevel::Debug,   (FMT(__VA_ARGS__)))
 #define DECODER_WARN(...) NS_WARNING(nsPrintfCString(FMT(__VA_ARGS__)).get())
 #define DUMP_LOG(...) NS_DebugBreak(NS_DEBUG_WARNING, nsPrintfCString(FMT(__VA_ARGS__)).get(), nullptr, nullptr, -1)
 
 // Used by StateObject and its sub-classes
 #define SFMT(x, ...) "Decoder=%p state=%s " x, mMaster->mDecoderID, ToStateStr(GetState()), ##__VA_ARGS__
 #define SLOG(...) MOZ_LOG(gMediaDecoderLog, LogLevel::Debug, (SFMT(__VA_ARGS__)))
 #define SWARN(...) NS_WARNING(nsPrintfCString(SFMT(__VA_ARGS__)).get())
+#define SDUMP(...) NS_DebugBreak(NS_DEBUG_WARNING, nsPrintfCString(SFMT(__VA_ARGS__)).get(), nullptr, nullptr, -1)
 
 // Certain constants get stored as member variables and then adjusted by various
 // scale factors on a per-decoder basis. We want to make sure to avoid using these
 // constants directly, so we put them in a namespace.
 namespace detail {
 
 // If audio queue has less than this many usecs of decoded audio, we won't risk
 // trying to decode the video, we'll skip decoding video up to the next
@@ -222,16 +224,18 @@ public:
   virtual bool HandleEndOfStream() { return false; }
 
   virtual bool HandleWaitingForData() { return false; }
 
   virtual RefPtr<MediaDecoder::SeekPromise> HandleSeek(SeekTarget aTarget) = 0;
 
   virtual bool HandleAudioCaptured() { return false; }
 
+  virtual void DumpDebugInfo() {}
+
 protected:
   using Master = MediaDecoderStateMachine;
   explicit StateObject(Master* aPtr) : mMaster(aPtr) {}
   TaskQueue* OwnerThread() const { return mMaster->mTaskQueue; }
   MediaResource* Resource() const { return mMaster->mResource; }
   MediaDecoderReaderWrapper* Reader() const { return mMaster->mReader; }
   const MediaInfo& Info() const { return mMaster->Info(); }
 
@@ -658,16 +662,21 @@ public:
   bool HandleAudioCaptured() override
   {
     MaybeStopPrerolling();
     // MediaSink is changed. Schedule Step() to check if we can start playback.
     mMaster->ScheduleStateMachine();
     return true;
   }
 
+  void DumpDebugInfo() override
+  {
+    SDUMP("mIsPrerolling=%d", mMaster->mIsPrerolling);
+  }
+
 private:
   void CheckSlowDecoding(TimeStamp aDecodeStart)
   {
     // For non async readers, if the requested video sample was slow to
     // arrive, increase the amount of audio we buffer to ensure that we
     // don't run out of audio. This is unnecessary for async readers,
     // since they decode audio and video on different threads so they
     // are unlikely to run out of decoded audio.
@@ -3043,25 +3052,26 @@ void
 MediaDecoderStateMachine::DumpDebugInfo()
 {
   MOZ_ASSERT(NS_IsMainThread());
 
   // It is fine to capture a raw pointer here because MediaDecoder only call
   // this function before shutdown begins.
   nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction([this] () {
     mMediaSink->DumpDebugInfo();
+    mStateObj->DumpDebugInfo();
     DUMP_LOG(
       "GetMediaTime=%lld GetClock=%lld mMediaSink=%p "
       "mState=%s mPlayState=%d mSentFirstFrameLoadedEvent=%d IsPlaying=%d "
       "mAudioStatus=%s mVideoStatus=%s mDecodedAudioEndTime=%lld mDecodedVideoEndTime=%lld "
-      "mIsPrerolling=%d mAudioCompleted=%d mVideoCompleted=%d",
+      "mAudioCompleted=%d mVideoCompleted=%d",
       GetMediaTime(), mMediaSink->IsStarted() ? GetClock() : -1, mMediaSink.get(),
       ToStateStr(), mPlayState.Ref(), mSentFirstFrameLoadedEvent, IsPlaying(),
       AudioRequestStatus(), VideoRequestStatus(), mDecodedAudioEndTime, mDecodedVideoEndTime,
-      mIsPrerolling, mAudioCompleted.Ref(), mVideoCompleted.Ref());
+      mAudioCompleted.Ref(), mVideoCompleted.Ref());
   });
 
   OwnerThread()->DispatchStateChange(r.forget());
 }
 
 void MediaDecoderStateMachine::AddOutputStream(ProcessedMediaStream* aStream,
                                                bool aFinishWhenEnded)
 {