--- a/dom/media/MediaDecoderStateMachine.cpp
+++ b/dom/media/MediaDecoderStateMachine.cpp
@@ -249,17 +249,16 @@ MediaDecoderStateMachine::MediaDecoderSt
   mAmpleAudioThresholdUsecs(detail::AMPLE_AUDIO_USECS),
   mQuickBufferingLowDataThresholdUsecs(detail::QUICK_BUFFERING_LOW_DATA_USECS),
   mIsAudioPrerolling(false),
   mIsVideoPrerolling(false),
   mAudioCaptured(false),
   INIT_WATCHABLE(mAudioCompleted, false),
   INIT_WATCHABLE(mVideoCompleted, false),
   mNotifyMetadataBeforeFirstFrame(false),
-  mDispatchedEventToDecode(false),
   mQuickBuffering(false),
   mMinimizePreroll(false),
   mDecodeThreadWaiting(false),
   mDecodingFirstFrame(true),
   mSentLoadedMetadataEvent(false),
   mSentFirstFrameLoadedEvent(false),
   mSentPlaybackEndedEvent(false),
   mVideoDecodeSuspended(false),

--- a/dom/media/MediaDecoderStateMachine.h
+++ b/dom/media/MediaDecoderStateMachine.h
@@ -865,21 +865,16 @@ private:
   // Flag whether we notify metadata before decoding the first frame or after.
   //
   // Note that the odd semantics here are designed to replicate the current
   // behavior where we notify the decoder each time we come out of dormant, but
   // send suppressed event visibility for those cases. This code can probably be
   // simplified.
   bool mNotifyMetadataBeforeFirstFrame;
 
-  // True if we've dispatched an event to the decode task queue to call
-  // DecodeThreadRun(). We use this flag to prevent us from dispatching
-  // unnecessary runnables, since the decode thread runs in a loop.
-  bool mDispatchedEventToDecode;
-
   // If this is true while we're in buffering mode, we can exit early,
   // as it's likely we may be able to playback. This happens when we enter
   // buffering mode soon after the decode starts, because the decode-ahead
   // ran fast enough to exhaust all data while the download is starting up.
   // Synchronised via decoder monitor.
   bool mQuickBuffering;
 
   // True if we should not decode/preroll unnecessary samples, unless we're