--- a/dom/audiochannel/AudioChannelAgent.cpp
+++ b/dom/audiochannel/AudioChannelAgent.cpp
@@ -101,23 +101,16 @@ AudioChannelAgent::FindCorrectWindow(nsP
   if (!doc) {
     return NS_OK;
   }
 
   if (nsContentUtils::IsChromeDoc(doc)) {
     return NS_OK;
   }
 
-  nsAutoCString systemAppUrl;
-  nsresult rv =
-    mozilla::Preferences::GetCString("b2g.system_startup_url", systemAppUrl);
-  if (NS_FAILED(rv)) {
-    return NS_OK;
-  }
-
   nsCOMPtr<nsIPrincipal> principal = doc->NodePrincipal();
   nsCOMPtr<nsIURI> uri;
   principal->GetURI(getter_AddRefs(uri));
 
   if (uri) {
     nsAutoCString spec;
     uri->GetSpec(spec);