Always treat .localhost as loopback

net/dns/host_resolver_impl_unittest.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 "net/dns/host_resolver_impl.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/bind.h"
@@ skipping 532 matching lines @@
 
   Request* req = CreateRequest("just.testing", 80);
   EXPECT_EQ(ERR_IO_PENDING, req->Resolve());
   EXPECT_EQ(OK, req->WaitForResult());
 
   EXPECT_TRUE(req->HasOneAddress("192.168.1.42", 80));
 
   EXPECT_EQ("just.testing", proc_->GetCaptureList()[0].hostname);
 }
 
+TEST_F(HostResolverImplTest, LocalhostLookup) {
+  proc_->SignalMultiple(1u);
+  Request* req = CreateRequest("foo.localhost", 80);
+  EXPECT_EQ(ERR_IO_PENDING, req->Resolve());
+  EXPECT_EQ(OK, req->WaitForResult());
+
+  EXPECT_TRUE(req->HasOneAddress("127.0.0.1", 80));
+
+  EXPECT_EQ("localhost.", proc_->GetCaptureList()[0].hostname);
+}
+
 TEST_F(HostResolverImplTest, EmptyListMeansNameNotResolved) {
   proc_->AddRuleForAllFamilies("just.testing", "");
   proc_->SignalMultiple(1u);
 
   Request* req = CreateRequest("just.testing", 80);
   EXPECT_EQ(ERR_IO_PENDING, req->Resolve());
   EXPECT_EQ(ERR_NAME_NOT_RESOLVED, req->WaitForResult());
   EXPECT_EQ(0u, req->NumberOfAddresses());
   EXPECT_EQ("just.testing", proc_->GetCaptureList()[0].hostname);
 }
@@ skipping 1533 matching lines @@
 
   EXPECT_EQ(OK, requests_[0]->WaitForResult());
   EXPECT_TRUE(requests_[0]->HasOneAddress("192.168.0.1", 80));
   EXPECT_EQ(OK, requests_[1]->WaitForResult());
   EXPECT_TRUE(requests_[1]->HasOneAddress("192.168.0.2", 80));
   EXPECT_EQ(OK, requests_[2]->WaitForResult());
   EXPECT_TRUE(requests_[2]->HasOneAddress("192.168.0.3", 80));
 }
 
 }  // namespace net