Mojo: Add a WebSocket/Client interface and hook it up to the HTML viewer.

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

 // Copyright 2014 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.
 
 import "mojo/services/public/interfaces/network/cookie_store.mojom"
 import "mojo/services/public/interfaces/network/url_loader.mojom"
+import "mojo/services/public/interfaces/network/web_socket.mojom"
 
 module mojo {
 
 interface NetworkService {
   CreateURLLoader(URLLoader&? loader);
 
   GetCookieStore(CookieStore&? cookie_store);
 
+  CreateWebSocket(WebSocket& socket);
+
   // TODO(darin): Add other methods here.
 };
 
 }