Add HttpProtocolHandler and convert everything to use it

ios/chrome/browser/ios_chrome_io_thread.mm

 // 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.
 
 #include "ios/chrome/browser/ios_chrome_io_thread.h"
 
 #include <stddef.h>
 
 #include <utility>
 #include <vector>
@@ skipping 999 matching lines @@
   context->set_cert_verifier(globals->cert_verifier.get());
   context->set_transport_security_state(
       globals->transport_security_state.get());
   context->set_cert_transparency_verifier(
       globals->cert_transparency_verifier.get());
   context->set_ssl_config_service(globals->ssl_config_service.get());
   context->set_http_auth_handler_factory(
       globals->http_auth_handler_factory.get());
   context->set_proxy_service(globals->system_proxy_service.get());
 
-  net::URLRequestJobFactoryImpl* system_job_factory =
-      new net::URLRequestJobFactoryImpl();
+  std::unique_ptr<net::URLRequestJobFactoryImpl> system_job_factory =
+      net::URLRequestJobFactoryImpl::CreateWithDefaultProtocolHandlers();
   // Data URLs are always loaded through the system request context on iOS
   // (due to UIWebView limitations).
   bool set_protocol = system_job_factory->SetProtocolHandler(
       url::kDataScheme, base::WrapUnique(new net::DataProtocolHandler()));
   DCHECK(set_protocol);
-  globals->system_url_request_job_factory.reset(system_job_factory);
+  globals->system_url_request_job_factory = std::move(system_job_factory);
   context->set_job_factory(globals->system_url_request_job_factory.get());
 
   context->set_cookie_store(globals->system_cookie_store.get());
   context->set_channel_id_service(globals->system_channel_id_service.get());
   context->set_network_delegate(globals->system_network_delegate.get());
   context->set_http_user_agent_settings(
       globals->http_user_agent_settings.get());
   context->set_network_quality_estimator(
       globals->network_quality_estimator.get());
   context->set_backoff_manager(globals->url_request_backoff_manager.get());
 
   context->set_http_server_properties(
       globals->http_server_properties->GetWeakPtr());
 
   net::HttpNetworkSession::Params system_params;
   InitializeNetworkSessionParamsFromGlobals(*globals, &system_params);
   net::URLRequestContextBuilder::SetHttpNetworkSessionComponents(
       context, &system_params);
 
   globals->system_http_network_session.reset(
       new net::HttpNetworkSession(system_params));
   globals->system_http_transaction_factory.reset(
       new net::HttpNetworkLayer(globals->system_http_network_session.get()));
   context->set_http_transaction_factory(
       globals->system_http_transaction_factory.get());
 
   return context;
 }