Avoid doing concurrent DNS resolves of the same hostname

net/http/http_cache.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 "net/http/http_cache.h"
 
 #include <algorithm>
 
 #include "base/compiler_specific.h"
 
@@ skipping 942 matching lines @@
     read_offset_ += result;
   } else if (result == 0) {  // end of file
     cache_->DoneReadingFromEntry(entry_, this);
     entry_ = NULL;
   }
   HandleResult(result);
 }
 
 //-----------------------------------------------------------------------------
 
-HttpCache::HttpCache(ProxyService* proxy_service,
+HttpCache::HttpCache(HostResolver* host_resolver,
+                     ProxyService* proxy_service,
                      const std::wstring& cache_dir,
                      int cache_size)
     : disk_cache_dir_(cache_dir),
       mode_(NORMAL),
       type_(DISK_CACHE),
-      network_layer_(HttpNetworkLayer::CreateFactory(proxy_service)),
+      network_layer_(HttpNetworkLayer::CreateFactory(
+          host_resolver, proxy_service)),
       ALLOW_THIS_IN_INITIALIZER_LIST(task_factory_(this)),
       in_memory_cache_(false),
       cache_size_(cache_size) {
 }
 
 HttpCache::HttpCache(HttpNetworkSession* session,
                      const std::wstring& cache_dir,
                      int cache_size)
     : disk_cache_dir_(cache_dir),
       mode_(NORMAL),
       type_(DISK_CACHE),
       network_layer_(HttpNetworkLayer::CreateFactory(session)),
       ALLOW_THIS_IN_INITIALIZER_LIST(task_factory_(this)),
       in_memory_cache_(false),
       cache_size_(cache_size) {
 }
 
-HttpCache::HttpCache(ProxyService* proxy_service, int cache_size)
+HttpCache::HttpCache(HostResolver* host_resolver,
+                     ProxyService* proxy_service,
+                     int cache_size)
     : mode_(NORMAL),
       type_(MEMORY_CACHE),
-      network_layer_(HttpNetworkLayer::CreateFactory(proxy_service)),
+      network_layer_(HttpNetworkLayer::CreateFactory(
+          host_resolver, proxy_service)),
       ALLOW_THIS_IN_INITIALIZER_LIST(task_factory_(this)),
       in_memory_cache_(true),
       cache_size_(cache_size) {
 }
 
 HttpCache::HttpCache(HttpTransactionFactory* network_layer,
                      disk_cache::Backend* disk_cache)
     : mode_(NORMAL),
       type_(DISK_CACHE),
       network_layer_(network_layer),
@@ skipping 474 matching lines @@
       static_cast<net::HttpNetworkLayer*>(network_layer_.get());
   HttpNetworkSession* session = network->GetSession();
   if (session) {
     session->connection_pool()->CloseIdleSockets();
   }
 }
 
 //-----------------------------------------------------------------------------
 
 }  // namespace net