Remove net-internals page for throttling, introduce flag for extension devs instead.

chrome/browser/resources/net_internals/index.js

 // Copyright (c) 2012 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.
 
 <include src="util.js"/>
 <include src="table_printer.js"/>
 <include src="view.js"/>
 <include src="tab_switcher_view.js"/>
 <include src="import_view.js"/>
 <include src="capture_view.js"/>
@@ skipping 22 matching lines @@
 <include src="timeline_data_series.js"/>
 <include src="timeline_graph_view.js"/>
 <include src="timeline_view.js"/>
 <include src="log_view_painter.js"/>
 <include src="log_grouper.js"/>
 <include src="proxy_view.js"/>
 <include src="socket_pool_wrapper.js"/>
 <include src="sockets_view.js"/>
 <include src="spdy_view.js"/>
 <include src="service_providers_view.js"/>
-<include src="http_throttling_view.js"/>
 <include src="logs_view.js"/>
 <include src="prerender_view.js"/>
 <include src="chromeos_view.js"/>
 <include src="http_pipeline_view.js"/>
 
 document.addEventListener('DOMContentLoaded', function() {
   MainView.getInstance();  // from main.js
 });