Better match IE's proxy settings....

net/proxy/proxy_script_fetcher.h

 // Copyright (c) 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.
 
 // ProxyScriptFetcher is an async interface for fetching a proxy auto config
 // script. It is specific to fetching a PAC script; enforces timeout, max-size,
 // status code.
 
 #ifndef NET_PROXY_PROXY_SCRIPT_FETCHER_H_
 #define NET_PROXY_PROXY_SCRIPT_FETCHER_H_
 
+#include <string>
+
 #include "net/base/completion_callback.h"
 #include "testing/gtest/include/gtest/gtest_prod.h"
 
 class GURL;
 class URLRequestContext;
 
 namespace net {
 
 class ProxyScriptFetcher {
  public:
   // Destruction should cancel any outstanding requests.
   virtual ~ProxyScriptFetcher() {}
 
   // Downloads the given PAC URL, and invokes |callback| on completion.
   // On success |callback| is executed with a result code of OK, and a
   // string of the response bytes. On failure, the result bytes is an empty
   // string, and the result code is a network error. Some special network
   // errors that may occur are:
   //
   //    ERR_TIMED_OUT         -- the fetch took too long to complete.
   //    ERR_FILE_TOO_BIG      -- the response's body was too large.
   //    ERR_PAC_STATUS_NOT_OK -- non-200 HTTP status code.
   //    ERR_NOT_IMPLEMENTED   -- the response required authentication.
   //
   // If the request is cancelled (either using the "Cancel()" method or by
   // deleting |this|), then no callback is invoked.
   //
   // Only one fetch is allowed to be outstanding at a time.
-  virtual void Fetch(const GURL& url, std::string* bytes,
-                     CompletionCallback* callback) = 0;
+  virtual int Fetch(const GURL& url, std::string* bytes,
+                    CompletionCallback* callback) = 0;
 
   // Aborts the in-progress fetch (if any).
   virtual void Cancel() = 0;
 
   // Create a ProxyScriptFetcher that uses |url_request_context|.
   static ProxyScriptFetcher* Create(URLRequestContext* url_request_context);
 
   // --------------------------------------------------------------------------
   // Testing helpers (only available to unit-tests).
   // --------------------------------------------------------------------------
  private:
   FRIEND_TEST(ProxyScriptFetcherTest, Hang);
   FRIEND_TEST(ProxyScriptFetcherTest, TooLarge);
 
   // Sets the maximum duration for a fetch to |timeout_ms|. Returns the previous
   // bound.
   static int SetTimeoutConstraintForUnittest(int timeout_ms);
 
   // Sets the maximum response size for a fetch to |size_bytes|. Returns the
   // previous bound.
   static size_t SetSizeConstraintForUnittest(size_t size_bytes);
 };
 
 }  // namespace net
 
 #endif  // NET_PROXY_PROXY_SCRIPT_FETCHER_H_