Bug 834146 - [Audio] When initilizing AudioChannelAgent, we should set visibility correctly in that time. r=kinetik, a=tef+

content/html/content/src/nsHTMLMediaElement.cpp

@@ -3612,6 +3612,13 @@ void nsHTMLMediaElement::UpdateAudioChannelPlayingState()
         return;
       }
       mAudioChannelAgent->Init(mAudioChannelType, this);
+
+      nsCOMPtr<nsIDOMDocument> domDoc = do_QueryInterface(OwnerDoc());
+      if (domDoc) {
+        bool hidden = false;
+        domDoc->GetHidden(&hidden);
+        mAudioChannelAgent->SetVisibilityState(!hidden);
+      }
     }
 
     if (mPlayingThroughTheAudioChannel) {