Add a feature flag for network service and about:flags entry for it.

content/browser/appcache/appcache_job.cc

 // Copyright (c) 2017 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 "content/browser/appcache/appcache_job.h"
 
 #include "base/command_line.h"
 #include "content/browser/appcache/appcache_request.h"
 #include "content/browser/appcache/appcache_response.h"
 #include "content/browser/appcache/appcache_url_loader_job.h"
 #include "content/browser/appcache/appcache_url_request_job.h"
-#include "content/public/common/content_switches.h"
+#include "content/public/common/content_features.h"
 #include "net/http/http_request_headers.h"
 #include "net/http/http_response_headers.h"
 #include "net/http/http_util.h"
 
 namespace content {
 
 std::unique_ptr<AppCacheJob> AppCacheJob::Create(
     bool is_main_resource,
     AppCacheHost* host,
     AppCacheStorage* storage,
     AppCacheRequest* request,
     net::NetworkDelegate* network_delegate,
     const OnPrepareToRestartCallback& restart_callback) {
   std::unique_ptr<AppCacheJob> job;
-  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kEnableNetworkService)) {
+  if (base::FeatureList::IsEnabled(features::kNetworkService)) {
     job.reset(
         new AppCacheURLLoaderJob(*(request->GetResourceRequest()), storage));
   } else {
     job.reset(new AppCacheURLRequestJob(request->GetURLRequest(),
                                         network_delegate, storage, host,
                                         is_main_resource, restart_callback));
   }
   return job;
 }
 
@@ skipping 72 matching lines @@
   // Make a copy of the full response headers and fix them up
   // for the range we'll be returning.
   range_response_info_.reset(
       new net::HttpResponseInfo(*info_->http_response_info()));
   net::HttpResponseHeaders* headers = range_response_info_->headers.get();
   headers->UpdateWithNewRange(range_requested_, resource_size,
                               true /* replace status line */);
 }
 
 }  // namespace content