Convert WindowOpenDisposition to an enum class.

chrome/browser/data_saver/data_saver_browsertest.cc

 // Copyright 2015 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 <string>
 
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_commands.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
@@ skipping 82 matching lines @@
   ASSERT_TRUE(test_server_->Start());
   EnableDataSaver(true);
 
   expected_save_data_header_ = "on";
   ui_test_utils::NavigateToURL(browser(),
                                test_server_->GetURL("/google/google.html"));
 
   // Reload the webpage and expect the main and the subresources will get the
   // correct save-data header.
   expected_save_data_header_ = "on";
-  chrome::Reload(browser(), CURRENT_TAB);
+  chrome::Reload(browser(), WindowOpenDisposition::CURRENT_TAB);
   content::WaitForLoadStop(
       browser()->tab_strip_model()->GetActiveWebContents());
 
   // Reload the webpage with data saver disabled, and expect all the resources
   // will get no save-data header.
   EnableDataSaver(false);
   expected_save_data_header_ = "";
-  chrome::Reload(browser(), CURRENT_TAB);
+  chrome::Reload(browser(), WindowOpenDisposition::CURRENT_TAB);
   content::WaitForLoadStop(
       browser()->tab_strip_model()->GetActiveWebContents());
 }