Better match IE's proxy settings....

net/proxy/proxy_resolver_mac.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.
 
 #ifndef NET_PROXY_PROXY_RESOLVER_MAC_H_
 #define NET_PROXY_PROXY_RESOLVER_MAC_H_
 
 #include <string>
 
 #include "googleurl/src/gurl.h"
+#include "net/base/net_errors.h"
 #include "net/proxy/proxy_config_service.h"
 #include "net/proxy/proxy_resolver.h"
 
 namespace net {
 
 // Implementation of ProxyResolver that uses the Mac CFProxySupport to implement
 // proxies.
 class ProxyResolverMac : public ProxyResolver {
  public:
   ProxyResolverMac() : ProxyResolver(false /*expects_pac_bytes*/) {}
 
   // ProxyResolver methods:
   virtual int GetProxyForURL(const GURL& url,
                              ProxyInfo* results,
                              CompletionCallback* callback,
                              RequestHandle* request);
 
   virtual void CancelRequest(RequestHandle request) {
     NOTREACHED();
   }
 
  private:
-  virtual void SetPacScriptByUrlInternal(const GURL& pac_url) {
+  virtual int SetPacScript(const GURL& pac_url,
+                           const std::string& /*pac_bytes*/,
+                           CompletionCallback* /*callback*/) {
     pac_url_ = pac_url;
+    return OK;
   }
 
   GURL pac_url_;
 };
 
 class ProxyConfigServiceMac : public ProxyConfigService {
  public:
   // ProxyConfigService methods:
   virtual int GetProxyConfig(ProxyConfig* config);
 };
 
 }  // namespace net
 
 #endif  // NET_PROXY_PROXY_RESOLVER_MAC_H_