Remove unused WEBKIT_DEPRECATED thread

chrome/browser/extensions/extension_service_unittest.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 CHROME_BROWSER_EXTENSIONS_EXTENSION_SERVICE_UNITTEST_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_SERVICE_UNITTEST_H_
 
 #include "base/at_exit.h"
 #include "base/files/file_path.h"
 #include "base/files/scoped_temp_dir.h"
@@ skipping 64 matching lines @@
   base::ScopedTempDir temp_dir_;
   scoped_ptr<TestingProfile> profile_;
   base::FilePath extensions_install_dir_;
   base::FilePath data_dir_;
   // Managed by extensions::ExtensionSystemFactory.
   ExtensionService* service_;
   extensions::ManagementPolicy* management_policy_;
   size_t expected_extensions_count_;
   content::TestBrowserThread ui_thread_;
   content::TestBrowserThread db_thread_;
-  content::TestBrowserThread webkit_thread_;
   content::TestBrowserThread file_thread_;
   content::TestBrowserThread file_user_blocking_thread_;
   content::TestBrowserThread io_thread_;
 
 #if defined OS_CHROMEOS
   chromeos::ScopedTestDeviceSettingsService test_device_settings_service_;
   chromeos::ScopedTestCrosSettings test_cros_settings_;
   chromeos::ScopedTestUserManager test_user_manager_;
 #endif
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_SERVICE_UNITTEST_H_