--- a/dom/workers/WorkerPrivate.cpp
+++ b/dom/workers/WorkerPrivate.cpp
@@ -4270,25 +4270,25 @@ WorkerPrivate::Constructor(const GlobalO
 {
   return WorkerPrivate::Constructor(aGlobal, aScriptURL, false,
                                     WorkerTypeDedicated, EmptyCString(),
                                     nullptr, aRv);
 }
 
 // static
 bool
-WorkerPrivate::WorkerAvailable(JSContext* /* unused */, JSObject* /* unused */)
+WorkerPrivate::WorkerAvailable(JSContext* aCx, JSObject* /* unused */)
 {
   // If we're already on a worker workers are clearly enabled.
   if (!NS_IsMainThread()) {
     return true;
   }
 
   // If our caller is chrome, workers are always available.
-  if (nsContentUtils::IsCallerChrome()) {
+  if (nsContentUtils::IsSystemCaller(aCx)) {
     return true;
   }
 
   // Else check the pref.
   return Preferences::GetBool(PREF_WORKERS_ENABLED);
 }
 
 // static
@@ -4307,17 +4307,17 @@ ChromeWorkerPrivate::Constructor(const G
 bool
 ChromeWorkerPrivate::WorkerAvailable(JSContext* aCx, JSObject* /* unused */)
 {
   // Chrome is always allowed to use workers, and content is never
   // allowed to use ChromeWorker, so all we have to check is the
   // caller.  However, chrome workers apparently might not have a
   // system principal, so we have to check for them manually.
   if (NS_IsMainThread()) {
-    return nsContentUtils::IsCallerChrome();
+    return nsContentUtils::IsSystemCaller(aCx);
   }
 
   return GetWorkerPrivateFromContext(aCx)->IsChromeWorker();
 }
 
 // static
 already_AddRefed<WorkerPrivate>
 WorkerPrivate::Constructor(const GlobalObject& aGlobal,
@@ -4488,17 +4488,17 @@ WorkerPrivate::GetLoadInfo(JSContext* aC
     AssertIsOnMainThread();
 
     // Make sure that the IndexedDatabaseManager is set up
     Unused << NS_WARN_IF(!IndexedDatabaseManager::GetOrCreate());
 
     nsIScriptSecurityManager* ssm = nsContentUtils::GetSecurityManager();
     MOZ_ASSERT(ssm);
 
-    bool isChrome = nsContentUtils::IsCallerChrome();
+    bool isChrome = nsContentUtils::IsSystemCaller(aCx);
 
     // First check to make sure the caller has permission to make a privileged
     // worker if they called the ChromeWorker/ChromeSharedWorker constructor.
     if (aIsChromeWorker && !isChrome) {
       return NS_ERROR_DOM_SECURITY_ERR;
     }
 
     // Chrome callers (whether creating a ChromeWorker or Worker) always get the