[WIP Prototype] ES6 https://html.spec.whatwg.org/#fetch-a-single-module-script implementation

third_party/WebKit/Source/core/loader/modulescript/ModuleTreeLinkerRegistry.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/ModuleTreeLinkerRegistry.h"
+
+#include "core/loader/modulescript/ModuleTreeLinker.h"
+
+namespace blink {
+
+DEFINE_TRACE(ModuleTreeLinkerRegistry) {
+  visitor->trace(m_activeTreeLinkers);
+}
+
+ModuleTreeLinker* ModuleTreeLinkerRegistry::fetch(const KURL& url,
+                                                  const KURL& baseURL,
+                                                  Modulator* modulator,
+                                                  ModuleTreeClient* client) {
+  ModuleTreeLinker* fetcher =
+      ModuleTreeLinker::fetch(url, baseURL, modulator, this, client);
+  DCHECK(fetcher->isFetching());
+  m_activeTreeLinkers.add(fetcher);
+  return fetcher;
+}
+
+void ModuleTreeLinkerRegistry::releaseFinishedFetcher(
+    ModuleTreeLinker* fetcher) {
+  DCHECK(fetcher->hasFinished());
+
+  auto it = m_activeTreeLinkers.find(fetcher);
+  DCHECK_NE(it, m_activeTreeLinkers.end());
+  m_activeTreeLinkers.remove(it);
+}
+
+}  // namespace blink