[ES6 modules] Introduce ModuleScriptLoader

third_party/WebKit/Source/core/loader/modulescript/ModuleScriptLoaderRegistry.cpp

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "core/loader/modulescript/ModuleScriptLoaderRegistry.h"
+
+#include "core/loader/modulescript/ModuleScriptLoader.h"
+
+namespace blink {
+
+DEFINE_TRACE(ModuleScriptLoaderRegistry) {
+  visitor->trace(m_activeLoaders);
+}
+
+ModuleScriptLoader* ModuleScriptLoaderRegistry::fetch(
+    const ModuleScriptFetchRequest& request,
+    ModuleGraphLevel level,
+    Modulator* modulator,
+    ResourceFetcher* fetcher,
+    ModuleScriptLoaderClient* client) {
+  ModuleScriptLoader* loader =
+      ModuleScriptLoader::create(modulator, this, client);
+  DCHECK(loader->isInitialState());
+  m_activeLoaders.insert(loader);
+  loader->fetch(request, fetcher, level);
+  return loader;
+}
+
+void ModuleScriptLoaderRegistry::releaseFinishedLoader(
+    ModuleScriptLoader* loader) {
+  DCHECK(loader->hasFinished());
+
+  auto it = m_activeLoaders.find(loader);
+  DCHECK_NE(it, m_activeLoaders.end());
+  m_activeLoaders.erase(it);
+}
+
+}  // namespace blink