Remove the dependence on BrowserThread::FILE for

net/proxy/proxy_service.h

 // Copyright (c) 2012 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_SERVICE_H_
 #define NET_PROXY_PROXY_SERVICE_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 274 matching lines @@
   // hardcoded proxy fallback list (|pac_string|) for every URL.
   //
   // |pac_string| is a list of proxy servers, in the format that a PAC script
   // would return it. For example, "PROXY foobar:99; SOCKS fml:2; DIRECT"
   static std::unique_ptr<ProxyService> CreateFixedFromPacResult(
       const std::string& pac_string);
 
   // Creates a config service appropriate for this platform that fetches the
   // system proxy settings.
   static std::unique_ptr<ProxyConfigService> CreateSystemProxyConfigService(
-      const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner,
-      const scoped_refptr<base::SingleThreadTaskRunner>& file_task_runner);
+      const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner);
 
   // This method should only be used by unit tests.
   void set_stall_proxy_auto_config_delay(base::TimeDelta delay) {
     stall_proxy_auto_config_delay_ = delay;
   }
 
   // This method should only be used by unit tests. Returns the previously
   // active policy.
   static const PacPollPolicy* set_pac_script_poll_policy(
       const PacPollPolicy* policy);
@@ skipping 175 matching lines @@
   SanitizeUrlPolicy sanitize_url_policy_;
 
   THREAD_CHECKER(thread_checker_);
 
   DISALLOW_COPY_AND_ASSIGN(ProxyService);
 };
 
 }  // namespace net
 
 #endif  // NET_PROXY_PROXY_SERVICE_H_