--- a/dom/media/MediaDecoder.h
+++ b/dom/media/MediaDecoder.h
@@ -488,19 +488,18 @@ private:
                                    uint32_t aDropped) override
   {
     GetFrameStatistics().NotifyDecodedFrames(aParsed, aDecoded, aDropped);
   }
 
   void UpdateReadyState()
   {
     MOZ_ASSERT(NS_IsMainThread());
-    if (!IsShutdown()) {
-      mOwner->UpdateReadyState();
-    }
+    MOZ_ASSERT(!IsShutdown());
+    mOwner->UpdateReadyState();
   }
 
   virtual MediaDecoderOwner::NextFrameStatus NextFrameStatus() { return mNextFrameStatus; }
   virtual MediaDecoderOwner::NextFrameStatus NextFrameBufferedStatus();
 
   // Returns a string describing the state of the media player internal
   // data. Used for debugging purposes.
   virtual void GetMozDebugReaderData(nsAString& aString) {}