[net] HostResolverImpl + DnsTransaction + DnsConfigService = Asynchronous DNS ready for experiments.

chrome/browser/io_thread.cc

 // 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 "chrome/browser/io_thread.h"
 
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/bind.h"
@@ skipping 22 matching lines @@
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/common/content_client.h"
 #include "content/public/common/url_fetcher.h"
 #include "net/base/cert_verifier.h"
 #include "net/base/cookie_monster.h"
 #include "net/base/default_origin_bound_cert_store.h"
 #include "net/base/host_cache.h"
 #include "net/base/host_resolver.h"
-#include "net/base/host_resolver_impl.h"
 #include "net/base/mapped_host_resolver.h"
 #include "net/base/net_util.h"
 #include "net/base/origin_bound_cert_service.h"
 #include "net/base/sdch_manager.h"
-#include "net/dns/async_host_resolver.h"
 #include "net/ftp/ftp_network_layer.h"
 #include "net/http/http_auth_filter.h"
 #include "net/http/http_auth_handler_factory.h"
 #include "net/http/http_network_layer.h"
 #include "net/http/http_network_session.h"
 #include "net/http/http_server_properties_impl.h"
 #include "net/proxy/proxy_config_service.h"
 #include "net/proxy/proxy_script_fetcher_impl.h"
 #include "net/proxy/proxy_service.h"
 
@@ skipping 70 matching lines @@
     // Parse the switch (it should be a non-negative integer).
     int n;
     if (base::StringToInt(s, &n) && n >= 0) {
       retry_attempts = static_cast<size_t>(n);
     } else {
       LOG(ERROR) << "Invalid switch for host resolver retry attempts: " << s;
     }
   }
 
   net::HostResolver* global_host_resolver = NULL;
-  if (command_line.HasSwitch(switches::kDnsServer)) {
-    std::string dns_ip_string =
-      command_line.GetSwitchValueASCII(switches::kDnsServer);
-    net::IPAddressNumber dns_ip_number;
-    if (net::ParseIPLiteralToNumber(dns_ip_string, &dns_ip_number)) {
-      global_host_resolver =
-        net::CreateAsyncHostResolver(parallelism, dns_ip_number, net_log);
-    } else {
-      LOG(ERROR) << "Invalid IP address specified for --dns-server: "
-                 << dns_ip_string;
-    }
+  if (command_line.HasSwitch(switches::kEnableAsyncDns)) {
+    global_host_resolver =
+        net::CreateAsyncHostResolver(parallelism, retry_attempts, net_log);
   }
 
   if (!global_host_resolver) {
     global_host_resolver =
       net::CreateSystemHostResolver(parallelism, retry_attempts, net_log);
   }
 
   // Determine if we should disable IPv6 support.
   if (!command_line.HasSwitch(switches::kEnableIPv6)) {
     if (command_line.HasSwitch(switches::kDisableIPv6)) {
@@ skipping 456 matching lines @@
       new net::HttpNetworkLayer(
           new net::HttpNetworkSession(system_params)));
   globals_->system_ftp_transaction_factory.reset(
       new net::FtpNetworkLayer(globals_->host_resolver.get()));
   globals_->system_request_context =
       ConstructSystemRequestContext(globals_, net_log_);
 
   sdch_manager_->set_sdch_fetcher(
       new SdchDictionaryFetcher(system_url_request_context_getter_.get()));
 }