Use mojo for Chrome Loading, Part 1

content/common/url_loader.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;
+
+[Native]
+struct URLRequest;
+
+[Native]
+struct URLResponseHead;
+
+[Native]
+struct URLLoaderStatus;
+
+interface URLLoader {
+  // Loads the given |request|, asynchronously producing |response|. Consult
+  // |response| to determine if the request resulted in an error, was
+  // redirected, or has a response body to be consumed.
+  // |request_id| is for compatibility with the existing ChromeIPC.
+  Load(int32 request_id,
+       URLRequest request,
+       URLLoaderClient client);
+
+  // If the request passed to |Load| had |auto_follow_redirects| set to false,
+  // then upon receiving an URLResponse with a non-NULL |redirect_url| field,
+  // |FollowRedirect| may be called to load the URL indicated by the redirect.
+  FollowRedirect();
+
+  // Cancels the request.
+  Cancel();
+};
+
+interface URLLoaderClient {
+  OnReceiveResponse(URLResponseHead head, handle<data_pipe_consumer> body);
+  OnComplete(URLLoaderStatus completion_status);
+};
+