Use ChromeThread::IO instead of virtual set_request_context

chrome/common/net/test_url_fetcher_factory.h

Index: chrome/common/net/test_url_fetcher_factory.h
diff --git a/chrome/common/net/test_url_fetcher_factory.h b/chrome/common/net/test_url_fetcher_factory.h
index 676cfe09e8b71a3addfa69672bf0619937abf1b5..b34c0a11a227d222975635899e55e9773e3f23a1 100644
--- a/chrome/common/net/test_url_fetcher_factory.h
+++ b/chrome/common/net/test_url_fetcher_factory.h
@@ -21,6 +21,8 @@
 // Typical usage:
 //   // TestURLFetcher requires a MessageLoop:
 //   MessageLoopForUI message_loop;
+//   // And io_thread to release URLRequestContextGetter in URLFetcher::Core.
+//   ChromeThread io_thread(ChromeThread::IO, &message_loop);
 //   // Create and register factory.
 //   TestURLFetcherFactory factory;
 //   URLFetcher::set_factory(&factory);
@@ -53,13 +55,6 @@ class TestURLFetcher : public URLFetcher {
   // Returns the data uploaded on this URLFetcher.
   const std::string& upload_data() const { return URLFetcher::upload_data(); }
 
-  // Overriden to do nothing. URLFetcher implementation add reference
-  // to request_context_getter in core_, but it might not be released
-  // because we wouldn't call Core::CancelURLRequest.
-  // Without this, we'll see leaks of URLRequestContext in test.
-  virtual void set_request_context(
-      URLRequestContextGetter* request_context_getter) {}
-
  private:
   const GURL original_url_;