Defer the proxy service initialization to first time resolve is called....

net/http/http_network_layer.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_HTTP_HTTP_NETWORK_LAYER_H_
 #define NET_HTTP_HTTP_NETWORK_LAYER_H_
 
 #include "base/ref_counted.h"
+#include "base/scoped_ptr.h"
 #include "net/http/http_transaction_factory.h"
 
 namespace net {
 
 class HttpNetworkSession;
 class ProxyInfo;
+class ProxyResolver;
 
 class HttpNetworkLayer : public HttpTransactionFactory {
  public:
   explicit HttpNetworkLayer(const ProxyInfo* pi);
   ~HttpNetworkLayer();
 
   // This function hides the details of how a network layer gets instantiated
   // and allows other implementations to be substituted.
   static HttpTransactionFactory* CreateFactory(const ProxyInfo* pi);
 
 #if defined(OS_WIN)
   // If value is true, then WinHTTP will be used.
   static void UseWinHttp(bool value);
 #endif
 
   // HttpTransactionFactory methods:
   virtual HttpTransaction* CreateTransaction();
   virtual HttpCache* GetCache();
   virtual AuthCache* GetAuthCache();
   virtual void Suspend(bool suspend);
 
  private:
 #if defined(OS_WIN)
   static bool use_winhttp_;
 #endif
 
+  // The pending proxy resolver to use when lazily creating session_.
+  // NULL afterwards.
+  scoped_ptr<ProxyResolver> proxy_resolver_;
+
   scoped_refptr<HttpNetworkSession> session_;
   bool suspended_;
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_HTTP_NETWORK_LAYER_H_