Update network service.

mojo/services/network/public/interfaces/url_loader_interceptor.mojom

+// Copyright 2015 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 mojo;
+
+import "mojo/public/interfaces/network/url_request.mojom";
+import "mojo/public/interfaces/network/url_response.mojom";
+
+// Factory for |URLLoaderInterceptor|. The factory is called once per URLLoader
+// and will be associated to it.
+interface URLLoaderInterceptorFactory {
+  Create(URLLoaderInterceptor& interceptor);
+};
+
+// An |URLLoaderInterceptor| is associated to a single URLLoader. It will be
+// able to intercept requests sent to the URLLoader and transform these or
+// directly respond to it. It will also intercept responses and transform them
+// or ask the network to continue with another request instead.
+// In case of redirect, the behavior is the following:
+// - If in the request |auto_follow_redirects| is true, the interceptor doesn't
+//   have access to any of the intermediate request(s) or response(s).
+//   Otherwise, it has access to intermediate responses as they are sent to the
+//   client and it is also notified when the client asks to follow a redirect.
+interface URLLoaderInterceptor {
+  // Intercept a request before it is sent to the network. This method can
+  // transform the request by returning the new requests to consider, or
+  // respond to the request itself by returning a response.
+  InterceptRequest(URLRequest request) =>
+      (URLLoaderInterceptorResponse response);
+
+  // Intercept |URLLoader.FollowRedirect()| calls. This method can either
+  // return null to let the call through, return a request to change the
+  // redirect, or respond to the redirect itself by returning a response.
+  InterceptFollowRedirect() => (URLLoaderInterceptorResponse? response);
+
+  // Intercept a response before it is sent to the loader client. This method
+  // can transform the response by returning the new response to send, ask
+  // the loader to load a new request instead by returning the request to load,
+  // or if the response is a redirect, follow it by returning null.
+  InterceptResponse(URLResponse response) =>
+      (URLLoaderInterceptorResponse? response);
+};
+
+// Response for the intercept methods. One and only one of the two fields
+// must be set. If |request| is set, the url loader will execute the request.
+// If |response| is set, the url loader will send it to its client. It is the
+// responsibility of the interceptor not to create infinite loops.
+// TODO(qsr): Change this to an union.
+struct URLLoaderInterceptorResponse {
+  URLRequest? request;
+  URLResponse? response;
+};