Avoid doing concurrent DNS resolves of the same hostname

net/http/http_network_transaction_unittest.cc

 // 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.
 
 #include <math.h>  // ceil
 
 #include "base/compiler_specific.h"
 #include "net/base/client_socket_factory.h"
 #include "net/base/completion_callback.h"
 #include "net/base/host_resolver_unittest.h"
@@ skipping 23 matching lines @@
 // HttpNetworkTransaction.
 class SessionDependencies {
  public:
   // Default set of dependencies -- "null" proxy service.
   SessionDependencies() : proxy_service(CreateNullProxyService()) {}
 
   // Custom proxy service dependency.
   explicit SessionDependencies(ProxyService* proxy_service)
       : proxy_service(proxy_service) {}
 
+  HostResolver host_resolver;
   scoped_ptr<ProxyService> proxy_service;
   MockClientSocketFactory socket_factory;
 };
 
 ProxyService* CreateFixedProxyService(const std::string& proxy) {
   net::ProxyConfig proxy_config;
   proxy_config.proxy_rules.ParseFromString(proxy);
   return ProxyService::CreateFixed(proxy_config);
 }
 
 
 HttpNetworkSession* CreateSession(SessionDependencies* session_deps) {
-  return new HttpNetworkSession(session_deps->proxy_service.get(),
+  return new HttpNetworkSession(&session_deps->host_resolver,
+                                session_deps->proxy_service.get(),
                                 &session_deps->socket_factory);
 }
 
 class HttpNetworkTransactionTest : public PlatformTest {
  public:
   virtual void TearDown() {
     // Empty the current queue.
     MessageLoop::current()->RunAllPending();
     PlatformTest::TearDown();
   }
@@ skipping 3047 matching lines @@
   TestCompletionCallback callback;
 
   int rv = trans->Start(&request, &callback);
   EXPECT_EQ(ERR_IO_PENDING, rv);
 
   rv = callback.WaitForResult();
   EXPECT_EQ(ERR_NAME_NOT_RESOLVED, rv);
 }
 
 }  // namespace net