Use ChromeThread::IO instead of virtual set_request_context

chrome/common/net/url_fetcher.h

 // Copyright (c) 2010 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.
 //
 // This file contains URLFetcher, a wrapper around URLRequest that handles
 // low-level details like thread safety, ref counting, and incremental buffer
 // reading.  This is useful for callers who simply want to get the data from a
 // URL and don't care about all the nitty-gritty details.
 
 #ifndef CHROME_COMMON_NET_URL_FETCHER_H_
@@ skipping 122 matching lines @@
 
   // Returns the current load flags.
   int load_flags() const;
 
   // Set extra headers on the request.  Must be called before the request
   // is started.
   void set_extra_request_headers(const std::string& extra_request_headers);
 
   // Set the URLRequestContext on the request.  Must be called before the
   // request is started.
-  virtual void set_request_context(
+  void set_request_context(
       URLRequestContextGetter* request_context_getter);
 
   // If |retry| is false, 5xx responses will be propagated to the observer,
   // if it is true URLFetcher will automatically re-execute the request,
   // after backoff_delay() elapses. URLFetcher has it set to true by default.
   void set_automatcally_retry_on_5xx(bool retry);
 
   // Returns the back-off delay before the request will be retried,
   // when a 5xx response was received.
   base::TimeDelta backoff_delay() const { return backoff_delay_; }
@@ skipping 37 matching lines @@
   bool automatically_retry_on_5xx_;
   // Back-off time delay. 0 by default.
   base::TimeDelta backoff_delay_;
 
   static bool g_interception_enabled;
 
   DISALLOW_COPY_AND_ASSIGN(URLFetcher);
 };
 
 #endif  // CHROME_COMMON_NET_URL_FETCHER_H_