--- a/dom/html/HTMLMediaElement.cpp
+++ b/dom/html/HTMLMediaElement.cpp
@@ -601,21 +601,16 @@ HTMLMediaElement::OnChannelRedirect(nsIC
 
   return NS_OK;
 }
 
 void HTMLMediaElement::ShutdownDecoder()
 {
   RemoveMediaElementFromURITable();
   NS_ASSERTION(mDecoder, "Must have decoder to shut down");
-  // TODO: This should be handled by ChangeNetworkState() so we have only one
-  // place to call StopProgress().
-  if (mNetworkState == nsIDOMHTMLMediaElement::NETWORK_LOADING) {
-    mDecoder->StopProgress();
-  }
   mDecoder->Shutdown();
   mDecoder = nullptr;
 }
 
 void HTMLMediaElement::AbortExistingLoads()
 {
   // Abort any already-running instance of the resource selection algorithm.
   mLoadWaitStatus = NOT_WAITING;
@@ -4034,17 +4029,17 @@ HTMLMediaElement::SetMediaKeys(mozilla::
     promise->MaybeReject(NS_ERROR_DOM_QUOTA_EXCEEDED_ERR);
     return promise.forget();
   }
   if (mMediaKeys) {
     // Existing MediaKeys object. Shut it down.
     mMediaKeys->Shutdown();
     mMediaKeys = nullptr;
   }
-  
+
   mMediaKeys = aMediaKeys;
   if (mMediaKeys) {
     if (NS_FAILED(mMediaKeys->Bind(this))) {
       promise->MaybeReject(NS_ERROR_DOM_INVALID_STATE_ERR);
       mMediaKeys = nullptr;
       return promise.forget();
     }
     if (mDecoder) {

--- a/dom/media/MediaDecoder.cpp
+++ b/dom/media/MediaDecoder.cpp
@@ -494,18 +494,19 @@ void MediaDecoder::Shutdown()
   // Force any outstanding seek and byterange requests to complete
   // to prevent shutdown from deadlocking.
   if (mResource) {
     mResource->Close();
   }
 
   ChangeState(PLAY_STATE_SHUTDOWN);
 
-  // If we hit this assertion, there might be a bug in network state transition.
-  NS_ASSERTION(!mProgressTimer, "Progress timer should've been stopped.");
+  if (mProgressTimer) {
+    StopProgress();
+  }
   mOwner = nullptr;
 
   MediaShutdownManager::Instance().Unregister(this);
 }
 
 MediaDecoder::~MediaDecoder()
 {
   MOZ_ASSERT(NS_IsMainThread());