Bug 1278452 - Remove unnecessary null checks in widget/gtk/. r=karlt.

|operator new| is infallible now.

--HG--
extra : rebase_source : 980a9097a84e75971bf514b10efe345abe09c51b

widget/gtk/WidgetTraceEvent.cpp

@@ -34,7 +34,7 @@ bool InitWidgetTracing()
 {
   sMutex = new Mutex("Event tracer thread mutex");
   sCondVar = new CondVar(*sMutex, "Event tracer thread condvar");
-  return sMutex && sCondVar;
+  return true;
 }
 
 void CleanUpWidgetTracing()