Bug 1881564 - Initialize module loader also for ServiceWorker to allow ChromeUtils.importESModule in DevTools ServiceWorker debugger global. r=yulia

Dynamic import is prevented by IsDynamicImportSupported, and now it now throws
TypeError instead of Error, and related wpt passes with it.

Differential Revision: https://phabricator.services.mozilla.com/D202494

dom/workers/ScriptLoader.cpp

@@ -517,9 +517,7 @@ already_AddRefed<WorkerScriptLoader> WorkerScriptLoader::Create(
   }
 
   // Set up the module loader, if it has not been initialzied yet.
-  if (!aWorkerPrivate->IsServiceWorker()) {
-    self->InitModuleLoader();
-  }
+  self->InitModuleLoader();
 
   return self.forget();
 }

dom/workers/loader/WorkerModuleLoader.cpp

@@ -147,6 +147,15 @@ already_AddRefed<ModuleLoadRequest> WorkerModuleLoader::CreateDynamicImport(
   return request.forget();
 }
 
+bool WorkerModuleLoader::IsDynamicImportSupported() {
+  WorkerPrivate* workerPrivate = GetCurrentThreadWorkerPrivate();
+  if (workerPrivate->IsServiceWorker()) {
+    return false;
+  }
+
+  return true;
+}
+
 bool WorkerModuleLoader::CanStartLoad(ModuleLoadRequest* aRequest,
                                       nsresult* aRvOut) {
   return true;

dom/workers/loader/WorkerModuleLoader.h

@@ -63,6 +63,8 @@ class WorkerModuleLoader : public JS::loader::ModuleLoaderBase {
       JS::Handle<JSString*> aSpecifier,
       JS::Handle<JSObject*> aPromise) override;
 
+  bool IsDynamicImportSupported() override;
+
   bool CanStartLoad(ModuleLoadRequest* aRequest, nsresult* aRvOut) override;
 
   // StartFetch is special for worker modules, as we need to move back to the

js/loader/ModuleLoaderBase.cpp

@@ -308,6 +308,12 @@ bool ModuleLoaderBase::HostImportModuleDynamically(
     return false;
   }
 
+  if (!loader->IsDynamicImportSupported()) {
+    JS_ReportErrorNumberASCII(aCx, js::GetErrorMessage, nullptr,
+                              JSMSG_DYNAMIC_IMPORT_NOT_SUPPORTED);
+    return false;
+  }
+
   auto result = loader->ResolveModuleSpecifier(script, specifier);
   if (result.isErr()) {
     JS::Rooted<JS::Value> error(aCx);

js/loader/ModuleLoaderBase.h

@@ -251,6 +251,8 @@ class ModuleLoaderBase : public nsISupports {
       JSContext* aCx, nsIURI* aURI, LoadedScript* aMaybeActiveScript,
       JS::Handle<JSString*> aSpecifier, JS::Handle<JSObject*> aPromise) = 0;
 
+  virtual bool IsDynamicImportSupported() { return true; }
+
   // Called when dynamic import started successfully.
   virtual void OnDynamicImportStarted(ModuleLoadRequest* aRequest) {}
 

testing/web-platform/meta/html/semantics/scripting-1/the-script-element/module/dynamic-import/microtasks/serviceworker.any.js.ini

@@ -1,3 +0,0 @@
-[serviceworker.any.serviceworker.html]
-  [import() should not drain the microtask queue if it fails because it's used in a ServiceWorker]
-    expected: FAIL

testing/web-platform/meta/service-workers/service-worker/no-dynamic-import.any.js.ini

@@ -1,11 +0,0 @@
-[no-dynamic-import.any.serviceworker.html]
-  expected:
-    if (os == "android") and fission: [OK, TIMEOUT]
-  [Module URL]
-    expected: FAIL
-
-  [Another module URL]
-    expected: FAIL
-
-  [Module data: URL]
-    expected: FAIL