[WIP] off-main-thread loading

content/common/worker_fetch_context_factory.mojom

+// 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.
+
+module content.mojom;
+
+import "url_loader_factory.mojom";
+
+interface ServiceWorkerClient {
+  // Called when the ServiceWorkerClient (which is Dedicated Worker or Shared
+  // Worker) is controlled by a new service worker.
+  SetControllerServiceWorker(int64 controller_version_id);
+};
+
+interface WorkerFetchContextFactory {
+  // Called from a dedicated (or shared) worker thread to create a worker fetch
+  // context.
+  // The browser process returns a URLLoaderFactory. SetControllerServiceWorker
+  // method of the passed ServiceWorkerClient interface will be called when the
+  // parent frame and the worker context is controlled by a service worker.
+  // |service_worker_provider_id| is the service worker provider id of the
+  // parent frame.
+  CreateWorkerFetchContext(associated URLLoaderFactory& loader,
+                           associated ServiceWorkerClient client,
+                           int32 service_worker_provider_id);
+
+  // Called from the service worker thread to get the URLLoaderFactory.
+  GetURLLoaderFactory(associated URLLoaderFactory& loader);
+};