Convert WindowOpenDisposition to an enum class.

ios/chrome/browser/interstitials/ios_chrome_controller_client.mm

 // 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 "ios/chrome/browser/interstitials/ios_chrome_controller_client.h"
 
 #include "base/logging.h"
 #include "ios/chrome/browser/application_context.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
 #include "ios/chrome/browser/pref_names.h"
@@ skipping 28 matching lines @@
   DCHECK(web_interstitial_);
   web_interstitial_->Proceed();
 }
 
 void IOSChromeControllerClient::Reload() {
   web_state_->GetNavigationManager()->Reload(true);
 }
 
 void IOSChromeControllerClient::OpenUrlInCurrentTab(const GURL& url) {
   web_state_->OpenURL(web::WebState::OpenURLParams(
-      url, web::Referrer(), CURRENT_TAB, ui::PAGE_TRANSITION_LINK, false));
+      url, web::Referrer(), WindowOpenDisposition::CURRENT_TAB,
+      ui::PAGE_TRANSITION_LINK, false));
 }
 
 const std::string& IOSChromeControllerClient::GetApplicationLocale() {
   return GetApplicationContext()->GetApplicationLocale();
 }
 
 PrefService* IOSChromeControllerClient::GetPrefService() {
   return ios::ChromeBrowserState::FromBrowserState(
              web_state_->GetBrowserState())
       ->GetPrefs();
 }
 
 const std::string IOSChromeControllerClient::GetExtendedReportingPrefName() {
   return std::string();
 }