Revert of Remove reference counting from HttpNetworkSession.

ios/crnet/crnet_environment.mm

 // 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.
 
 #include "ios/crnet/crnet_environment.h"
 
 #import <Foundation/Foundation.h>
 
 #include "base/at_exit.h"
 #include "base/command_line.h"
@@ skipping 428 matching lines @@
   if (!params.channel_id_service) {
     // The main context may not have a ChannelIDService, since it is lazily
     // constructed. If not, build an ephemeral ChannelIDService with no backing
     // disk store.
     // TODO(ellyjones): support persisting ChannelID.
     params.channel_id_service = new net::ChannelIDService(
         new net::DefaultChannelIDStore(NULL),
         base::WorkerPool::GetTaskRunner(true));
   }
 
-  // TODO(mmenke):  These really shouldn't be leaked.
-  //                See https://crbug.com/523858.
-  net::HttpNetworkSession* http_network_session =
-      new net::HttpNetworkSession(params);
-  net::HttpCache* main_cache = new net::HttpCache(
-      http_network_session, main_backend, true /* set_up_quic_server_info */);
+  net::HttpCache* main_cache = new net::HttpCache(params, main_backend);
   main_context_->set_http_transaction_factory(main_cache);
 
   // Cookies
   scoped_refptr<net::CookieStore> cookie_store =
       net::CookieStoreIOS::CreateCookieStoreFromNSHTTPCookieStorage();
   main_context_->set_cookie_store(cookie_store.get());
 
   net::URLRequestJobFactoryImpl* job_factory =
       new net::URLRequestJobFactoryImpl;
   job_factory->SetProtocolHandler(
@@ skipping 36 matching lines @@
       if (backend)
         backend->DoomAllEntries(client_callback);
   });
   int rc = cache->GetBackend(&backend, doom_callback);
   if (rc != net::ERR_IO_PENDING) {
     // GetBackend doesn't call the callback if it completes synchronously, so
     // call it directly here.
     doom_callback.Run(rc);
   }
 }