Use mojo for Chrome Loading, Part 1

content/common/url_loader_factory.mojom

+// 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.
+
+module content.mojom;
+
+import "url_loader.mojom";
+
+interface URLLoaderFactory {
+  // Creats a URLLoader and starts loading with the given |request|. |client|'s
+  // method will be called when certain events related to that loading
+  // (e.g., response arrival) happen. |request_id| is for compatibility with
+  // the existing Chrome IPC.
+  CreateLoaderAndStart(URLLoader& loader,
+                       int32 request_id,
+                       URLRequest request,
+                       URLLoaderClient client);
+};