--- a/dom/media/MediaDecoderStateMachine.cpp
+++ b/dom/media/MediaDecoderStateMachine.cpp
@@ -2614,23 +2614,23 @@ MediaDecoderStateMachine::ScheduleStateM
   MOZ_ASSERT(aMicroseconds > 0);
   if (mDispatchedStateMachine) {
     return;
   }
 
   TimeStamp now = TimeStamp::Now();
   TimeStamp target = now + TimeDuration::FromMicroseconds(aMicroseconds);
 
-  SAMPLE_LOG("Scheduling state machine for %lf ms from now", (target - now).ToMilliseconds());
-
-  RefPtr<MediaDecoderStateMachine> self = this;
-  mDelayedScheduler.Ensure(target, [self] () {
-    self->OnDelayedSchedule();
-  }, [self] () {
-    self->NotReached();
+  // It is OK to capture 'this' without causing UAF because the callback
+  // always happens before shutdown.
+  mDelayedScheduler.Ensure(target, [this] () {
+    mDelayedScheduler.CompleteRequest();
+    RunStateMachine();
+  }, [] () {
+    MOZ_DIAGNOSTIC_ASSERT(false);
   });
 }
 
 bool MediaDecoderStateMachine::OnTaskQueue() const
 {
   return OwnerThread()->IsCurrentThreadIn();
 }
 

--- a/dom/media/MediaDecoderStateMachine.h
+++ b/dom/media/MediaDecoderStateMachine.h
@@ -314,25 +314,16 @@ private:
   // Schedules the shared state machine thread to run the state machine.
   void ScheduleStateMachine();
 
   // Invokes ScheduleStateMachine to run in |aMicroseconds| microseconds,
   // unless it's already scheduled to run earlier, in which case the
   // request is discarded.
   void ScheduleStateMachineIn(int64_t aMicroseconds);
 
-  void OnDelayedSchedule()
-  {
-    MOZ_ASSERT(OnTaskQueue());
-    mDelayedScheduler.CompleteRequest();
-    ScheduleStateMachine();
-  }
-
-  void NotReached() { MOZ_DIAGNOSTIC_ASSERT(false); }
-
   // Discard audio/video data that are already played by MSG.
   void DiscardStreamData();
   bool HaveEnoughDecodedAudio();
   bool HaveEnoughDecodedVideo();
 
   // True if shutdown process has begun.
   bool IsShutdown() const;