Introduce Http{Request,Response} mojom structs.

mojo/services/network/public/interfaces/http_connection.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 "network/public/interfaces/url_loader.mojom";
+import "network/public/interfaces/http_message.mojom";
 import "network/public/interfaces/network_error.mojom";
 import "network/public/interfaces/web_socket.mojom";
 
 interface HttpConnection {
   // Sets the OS send buffer size (in bytes) for the underlying socket.
   SetSendBufferSize(uint32 size) => (NetworkError result);
 
   // Sets the OS receive buffer size (in bytes) for the underlying socket.
   SetReceiveBufferSize(uint32 size) => (NetworkError result);
 };
 
 interface HttpConnectionDelegate {
   // Called when an HTTP request is received.
-  OnReceivedRequest(URLRequest request) => (URLResponse response);
+  OnReceivedRequest(HttpRequest request) => (HttpResponse response);
 
   // Called when an WebSocket request is received.
   //
   // If the delegate decides to accept the request, it should respond with
   // non-null arguments in the callback. |send_stream| is a data pipe which
   // should remain open for the lifetime of the WebSocket. Data to send over the
   // WebSocket should be written to the producer end of the |send_stream|.
   // |web_socket| will be already connected. There is no need to call Connect()
   // on it. But |client| will still receive a DidConnect() notification.
-  OnReceivedWebSocketRequest(URLRequest request)
+  OnReceivedWebSocketRequest(HttpRequest request)
       => (WebSocket&? web_socket,
           handle<data_pipe_consumer>? send_stream,
           WebSocketClient? client);
 };