Bug 1388608: Add profiler labels for dispatching named runnables. r=mstange

MozReview-Commit-ID: 2vmVY38Kdll

--HG--
extra : rebase_source : 59415696d2d59becb541a950d4077ddebeeef3ca
extra : amend_source : 81c9b683e83abe370088e80716ea63d74c783700

xpcom/threads/nsThread.cpp

@@ -1561,6 +1561,9 @@ nsThread::ProcessNextEvent(bool aMayWait, bool* aResult)
         memcpy(sMainThreadRunnableName.begin(), name.BeginReading(), length);
         sMainThreadRunnableName[length] = '\0';
       }
+
+      AUTO_PROFILER_LABEL_DYNAMIC("nsThread::ProcessNextEvent", EVENTS,
+                                  name.get());
 #endif
       Maybe<AutoTimeDurationHelper> timeDurationHelper;
       if (priority == nsIRunnablePriority::PRIORITY_INPUT) {