--- a/dom/html/HTMLMediaElement.cpp
+++ b/dom/html/HTMLMediaElement.cpp
@@ -646,16 +646,22 @@ public:
 
     if (playingThroughTheAudioChannel != mPlayingThroughTheAudioChannel) {
       if (!MaybeCreateAudioChannelAgent()) {
         return;
       }
 
       mPlayingThroughTheAudioChannel = playingThroughTheAudioChannel;
       NotifyAudioChannelAgent(mPlayingThroughTheAudioChannel);
+
+      nsPIDOMWindowInner* window = mOwner->OwnerDoc()->GetInnerWindow();
+      if (window) {
+        mPlayingThroughTheAudioChannel ? window->AddPlayingElement(mOwner)
+                                       : window->RemovePlayingElement(mOwner);
+      }
     }
   }
 
   bool
   ShouldResetSuspend() const
   {
     // The disposable-pause should be clear after media starts playing.
     if (!mOwner->Paused() &&