Bug 1577537 - Exit MediaStreamGraphImpl::CollectReports early when there are no streams. r=padenot

Differential Revision: https://phabricator.services.mozilla.com/D44369

--HG--
extra : moz-landing-system : lando

dom/media/MediaStreamGraph.cpp

@@ -3361,13 +3361,10 @@ NS_IMETHODIMP
 MediaStreamGraphImpl::CollectReports(nsIHandleReportCallback* aHandleReport,
                                      nsISupports* aData, bool aAnonymize) {
   MOZ_ASSERT(NS_IsMainThread());
-  {
-    MonitorAutoLock mon(mMonitor);
-    if (LifecycleStateRef() >= LIFECYCLE_WAITING_FOR_THREAD_SHUTDOWN) {
-      // Shutting down, nothing to report.
-      FinishCollectReports(aHandleReport, aData, nsTArray<AudioNodeSizes>());
-      return NS_OK;
-    }
+  if (mMainThreadStreamCount == 0) {
+    // No streams to report.
+    FinishCollectReports(aHandleReport, aData, nsTArray<AudioNodeSizes>());
+    return NS_OK;
   }
 
   class Message final : public ControlMessage {