Bug 1447563 - Clear video outputs during shutdown. r=padenot

MozReview-Commit-ID: L1ZnhmxrPqa

--HG--
extra : rebase_source : b35a810559d4b5706c3cce5a42b58cf388246ba7

dom/media/MediaStreamGraph.cpp

@@ -2050,6 +2050,12 @@ MediaStream::RemoveAllListenersImpl()
   if (SourceMediaStream* source = AsSourceStream()) {
     source->RemoveAllDirectListeners();
   }
+
+  auto videoOutputs(mVideoOutputs);
+  for (auto& l : videoOutputs) {
+    l.mListener->NotifyRemoved();
+  }
+  mVideoOutputs.Clear();
 }
 
 void