Revert "Support replacement of IP address resolutions via command line flag"

chrome/browser/io_thread.cc

Index: chrome/browser/io_thread.cc
diff --git a/chrome/browser/io_thread.cc b/chrome/browser/io_thread.cc
index 5e40680860744a7e79384ab8a923a445f7019ec6..46e04bfbbbd3da0529c42c71cd8653bd01ffc63a 100644
--- a/chrome/browser/io_thread.cc
+++ b/chrome/browser/io_thread.cc
@@ -48,7 +48,6 @@
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/cookie_store_factory.h"
 #include "net/base/host_mapping_rules.h"
-#include "net/base/ip_mapping_rules.h"
 #include "net/base/net_util.h"
 #include "net/base/network_time_notifier.h"
 #include "net/base/sdch_manager.h"
@@ -61,7 +60,6 @@
 #include "net/dns/host_cache.h"
 #include "net/dns/host_resolver.h"
 #include "net/dns/mapped_host_resolver.h"
-#include "net/dns/mapped_ip_resolver.h"
 #include "net/ftp/ftp_network_layer.h"
 #include "net/http/http_auth_filter.h"
 #include "net/http/http_auth_handler_factory.h"
@@ -201,28 +199,17 @@ scoped_ptr<net::HostResolver> CreateGlobalHostResolver(net::NetLog* net_log) {
     global_host_resolver->SetDefaultAddressFamily(net::ADDRESS_FAMILY_IPV4);
   }
 
-  // If hostname or IP remappings were specified on the command-line, layer
-  // these rules on top of the real host resolver. Hostname remapping allows
-  // forwarding of all requests to hosts (matching a pattern) through a
-  // designated test server.   IP remapping allows for all IP resolutions that
-  // match a given pattern, such as those destined for a specific CDN, to be
-  // instead directed to a specific/alternate IP address.
-  if (command_line.HasSwitch(switches::kHostResolverRules)) {
-    scoped_ptr<net::MappedHostResolver> remapped_resolver(
-        new net::MappedHostResolver(global_host_resolver.Pass()));
-    remapped_resolver->SetRulesFromString(
-        command_line.GetSwitchValueASCII(switches::kHostResolverRules));
-    global_host_resolver = remapped_resolver.Pass();
-  }
-
-  if (command_line.HasSwitch(switches::kIpResolverRules)) {
-    scoped_ptr<net::MappedIPResolver> remapped_resolver(
-        new net::MappedIPResolver(global_host_resolver.Pass()));
-    remapped_resolver->SetRulesFromString(
-        command_line.GetSwitchValueASCII(switches::kIpResolverRules));
-    global_host_resolver = remapped_resolver.Pass();
-  }
-  return global_host_resolver.Pass();
+  // If hostname remappings were specified on the command-line, layer these
+  // rules on top of the real host resolver. This allows forwarding all requests
+  // through a designated test server.
+  if (!command_line.HasSwitch(switches::kHostResolverRules))
+    return global_host_resolver.PassAs<net::HostResolver>();
+
+  scoped_ptr<net::MappedHostResolver> remapped_resolver(
+      new net::MappedHostResolver(global_host_resolver.Pass()));
+  remapped_resolver->SetRulesFromString(
+      command_line.GetSwitchValueASCII(switches::kHostResolverRules));
+  return remapped_resolver.PassAs<net::HostResolver>();
 }
 
 // TODO(willchan): Remove proxy script fetcher context since it's not necessary