Add HttpProtocolHandler and convert everything to use it

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 <utility>
 
@@ skipping 462 matching lines @@
   net::HttpCache* main_cache =
       new net::HttpCache(http_network_session, std::move(main_backend),
                          true /* set_up_quic_server_info */);
   main_context_->set_http_transaction_factory(main_cache);
 
   // Cookies
   cookie_store_ = net::CookieStoreIOS::CreateCookieStore(
       [NSHTTPCookieStorage sharedHTTPCookieStorage]);
   main_context_->set_cookie_store(cookie_store_.get());
 
-  net::URLRequestJobFactoryImpl* job_factory =
-      new net::URLRequestJobFactoryImpl;
+  // TODO(mgersh): Fix this leak too. See https://crbug.com/523858
+  std::unique_ptr<net::URLRequestJobFactoryImpl> job_factory =
+      net::URLRequestJobFactoryImpl::CreateWithHttpProtocolHandlers();
   job_factory->SetProtocolHandler(
       "data", base::WrapUnique(new net::DataProtocolHandler));
 #if !defined(DISABLE_FILE_SUPPORT)
   job_factory->SetProtocolHandler(
       "file",
       base::MakeUnique<net::FileProtocolHandler>(file_thread_->task_runner()));
 #endif   // !defined(DISABLE_FILE_SUPPORT)
-  main_context_->set_job_factory(job_factory);
-
+  main_context_->set_job_factory(job_factory.release());
   main_context_->set_net_log(net_log_.get());
 }
 
 std::string CrNetEnvironment::user_agent() {
   const net::HttpUserAgentSettings* user_agent_settings =
       main_context_->http_user_agent_settings();
   if (!user_agent_settings) {
     return nullptr;
   }
 
   return user_agent_settings->GetUserAgent();
 }
 
 void CrNetEnvironment::ClearCache(ClearCacheCallback callback) {
   PostToNetworkThread(
       FROM_HERE, base::Bind(&net::ClearHttpCache, main_context_getter_,
                             network_io_thread_->task_runner(), base::Time(),
                             base::Time::Max(), base::BindBlock(callback)));
 }