MD Settings: Second try at fixing ResetSettingsHandler crash

chrome/browser/profile_resetter/brandcode_config_fetcher.cc

 // Copyright 2013 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.
 
 #include "chrome/browser/profile_resetter/brandcode_config_fetcher.h"
 
 #include <stddef.h>
 
+#include "base/callback_helpers.h"
 #include "base/macros.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/profile_resetter/brandcoded_default_settings.h"
 #include "libxml/parser.h"
 #include "net/base/load_flags.h"
 #include "net/http/http_response_headers.h"
 #include "net/url_request/url_fetcher.h"
 #include "net/url_request/url_request_status.h"
 
@@ skipping 161 matching lines @@
       config_fetcher_->GetResponseCode() == 200 &&
       config_fetcher_->GetResponseHeaders()->GetMimeType(&mime_type) &&
       mime_type == "text/xml" &&
       config_fetcher_->GetResponseAsString(&response_string)) {
     std::string master_prefs;
     XmlConfigParser::Parse(response_string, &master_prefs);
     default_settings_.reset(new BrandcodedDefaultSettings(master_prefs));
   }
   config_fetcher_.reset();
   download_timer_.Stop();
-  fetch_callback_.Run();
+  base::ResetAndReturn(&fetch_callback_).Run();
 }
 
 void BrandcodeConfigFetcher::OnDownloadTimeout() {
   if (config_fetcher_) {
     config_fetcher_.reset();
-    fetch_callback_.Run();
+    base::ResetAndReturn(&fetch_callback_).Run();
   }
 }