Remove the db_loop_ member variable which is a unused following r30163....

chrome/browser/net/chrome_url_request_context.h

 // Copyright (c) 2009 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 CHROME_BROWSER_NET_CHROME_URL_REQUEST_CONTEXT_H_
 #define CHROME_BROWSER_NET_CHROME_URL_REQUEST_CONTEXT_H_
 
 #include "base/file_path.h"
 #include "chrome/browser/net/url_request_context_getter.h"
 #include "chrome/common/appcache/chrome_appcache_service.h"
@@ skipping 298 matching lines @@
   std::string referrer_charset_;
   net::CookiePolicy::Type cookie_policy_type_;
   ChromeURLRequestContext::ExtensionPaths extension_paths_;
   FilePath user_script_dir_path_;
   Blacklist* blacklist_;
   net::StrictTransportSecurityState* strict_transport_security_state_;
   scoped_refptr<net::SSLConfigService> ssl_config_service_;
 
   FilePath profile_dir_path_;
 
-  // Values extracted from the browser process.
-  MessageLoop* db_loop_;
-
   DISALLOW_COPY_AND_ASSIGN(ChromeURLRequestContextFactory);
 };
 
 // Creates a proxy configuration using the overrides specified on the command
 // line. Returns NULL if the system defaults should be used instead.
 net::ProxyConfig* CreateProxyConfig(const CommandLine& command_line);
 
 #endif  // CHROME_BROWSER_NET_CHROME_URL_REQUEST_CONTEXT_H_