--- a/dom/worklet/Worklet.cpp
+++ b/dom/worklet/Worklet.cpp
@@ -385,19 +385,21 @@ ExecutionRunnable::RunOnWorkletThread()
     Worklet::CreateGlobalScope(jsapi.cx(), mWorkletType);
   MOZ_ASSERT(globalScope);
 
   AutoEntryScript aes(globalScope, "Worklet");
   cx = aes.cx();
 
   JS::Rooted<JSObject*> globalObj(cx, globalScope->GetGlobalJSObject());
 
+  NS_ConvertUTF16toUTF8 url(mHandler->URL());
+
   JS::CompileOptions compileOptions(cx);
   compileOptions.setIntroductionType("Worklet");
-  compileOptions.setFileAndLine(NS_ConvertUTF16toUTF8(mHandler->URL()).get(), 0);
+  compileOptions.setFileAndLine(url.get(), 0);
   compileOptions.setVersion(JSVERSION_DEFAULT);
   compileOptions.setIsRunOnce(true);
   compileOptions.setNoScriptRval(true);
 
   JSAutoCompartment comp(cx, globalObj);
 
   JS::Rooted<JS::Value> unused(cx);
   if (!JS::Evaluate(cx, compileOptions, mBuffer, &unused)) {