Bug 1613985 - Use default for equivalent-to-default constructors/destructors in dom/worklet. r=smaug

Depends on D66033

Differential Revision: https://phabricator.services.mozilla.com/D66034

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

dom/worklet/Worklet.cpp

@@ -264,7 +264,7 @@ class WorkletFetchHandler final : public PromiseNativeHandler,
     mPromises.AppendElement(aPromise);
   }
 
-  ~WorkletFetchHandler() {}
+  ~WorkletFetchHandler() = default;
 
   void AddPromise(Promise* aPromise) {
     MOZ_ASSERT(aPromise);