Avoid doing concurrent DNS resolves of the same hostname

net/url_request/url_request_unittest.h

 // Copyright (c) 2006-2008 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.
 
 #ifndef NET_URL_REQUEST_URL_REQUEST_UNITTEST_H_
 #define NET_URL_REQUEST_URL_REQUEST_UNITTEST_H_
 
 #include <stdlib.h>
 
 #include <sstream>
 #include <string>
 #include <vector>
 
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
 #include "base/path_service.h"
 #include "base/process_util.h"
 #include "base/string_util.h"
 #include "base/thread.h"
 #include "base/time.h"
 #include "base/waitable_event.h"
+#include "net/base/host_resolver.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
 #include "net/base/ssl_test_util.h"
 #include "net/http/http_network_layer.h"
 #include "net/url_request/url_request.h"
 #include "net/url_request/url_request_context.h"
 #include "net/proxy/proxy_service.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "googleurl/src/url_util.h"
 
 const int kHTTPDefaultPort = 1337;
 const int kFTPDefaultPort = 1338;
 
 const std::string kDefaultHostName("localhost");
 
 using base::TimeDelta;
 
 // This URLRequestContext does not use a local cache.
 class TestURLRequestContext : public URLRequestContext {
  public:
   TestURLRequestContext() {
+    host_resolver_ = new net::HostResolver;
     proxy_service_ = net::ProxyService::CreateNull();
     http_transaction_factory_ =
-        net::HttpNetworkLayer::CreateFactory(proxy_service_);
+        net::HttpNetworkLayer::CreateFactory(host_resolver_,
+            proxy_service_);
   }
 
   explicit TestURLRequestContext(const std::string& proxy) {
+    host_resolver_ = new net::HostResolver;
     net::ProxyConfig proxy_config;
     proxy_config.proxy_rules.ParseFromString(proxy);
     proxy_service_ = net::ProxyService::CreateFixed(proxy_config);
     http_transaction_factory_ =
-        net::HttpNetworkLayer::CreateFactory(proxy_service_);
+        net::HttpNetworkLayer::CreateFactory(host_resolver_,
+            proxy_service_);
   }
 
   virtual ~TestURLRequestContext() {
     delete http_transaction_factory_;
     delete proxy_service_;
+    delete host_resolver_;
   }
 };
 
 class TestDelegate : public URLRequest::Delegate {
  public:
   TestDelegate()
       : cancel_in_rr_(false),
         cancel_in_rs_(false),
         cancel_in_rd_(false),
         cancel_in_rd_pending_(false),
@@ skipping 473 matching lines @@
 
     MessageLoop::current()->Run();
     if (request.is_pending())
       return false;
 
     return true;
   }
 };
 
 #endif  // NET_URL_REQUEST_URL_REQUEST_UNITTEST_H_