Avoid doing concurrent DNS resolves of the same hostname

net/url_request/url_request_unittest.cc

 // Copyright (c) 2006-2009 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/url_request/url_request_unittest.h"
 
 #include "build/build_config.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
@@ skipping 27 matching lines @@
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/platform_test.h"
 
 using base::Time;
 
 namespace {
 
 class URLRequestHttpCacheContext : public URLRequestContext {
  public:
   URLRequestHttpCacheContext() {
+    host_resolver_ = new net::HostResolver;
     proxy_service_ = net::ProxyService::CreateNull();
     http_transaction_factory_ =
-        new net::HttpCache(net::HttpNetworkLayer::CreateFactory(proxy_service_),
-                           disk_cache::CreateInMemoryCacheBackend(0));
+        new net::HttpCache(
+          net::HttpNetworkLayer::CreateFactory(host_resolver_, proxy_service_),
+          disk_cache::CreateInMemoryCacheBackend(0));
     // In-memory cookie store.
     cookie_store_ = new net::CookieMonster();
   }
 
   virtual ~URLRequestHttpCacheContext() {
     delete cookie_store_;
     delete http_transaction_factory_;
     delete proxy_service_;
+    delete host_resolver_;
   }
 };
 
 class TestURLRequest : public URLRequest {
  public:
   TestURLRequest(const GURL& url, Delegate* delegate)
       : URLRequest(url, delegate) {
     set_context(new URLRequestHttpCacheContext());
   }
 };
@@ skipping 1726 matching lines @@
 
     int64 file_size = 0;
     file_util::GetFileSize(app_path, &file_size);
 
     EXPECT_TRUE(!r.is_pending());
     EXPECT_EQ(1, d.response_started_count());
     EXPECT_FALSE(d.received_data_before_response());
     EXPECT_EQ(d.bytes_received(), 0);
   }
 }