Implement ServiceWorkerFetchDispatcher::MaybeStartNavigationPreload().

content/browser/service_worker/service_worker_navigation_preload_fetcher.h

+// Copyright 2016 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.
+
+#ifndef CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_NAVIGATION_PRELOAD_FETCHER_H_
+#define CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_NAVIGATION_PRELOAD_FETCHER_H_
+
+#include "content/common/service_worker/fetch_event_dispatcher.mojom.h"
+
+namespace net {
+class URLRequest;
+}  // namespace net
+
+namespace content {
+
+// Class for fetching navigation requests for ServiceWorkers.
+// TODO(horo): Revise link when this lands in the spec:
+// https://github.com/w3c/ServiceWorker/issues/920
+class ServiceWorkerNavigationPreloadFetcher {
+ public:
+  static mojom::FetchEventPreloadHandlePtr Start(
+      net::URLRequest* original_request);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_NAVIGATION_PRELOAD_FETCHER_H_