Convert WindowOpenDisposition to an enum class.

chrome/browser/ui/cocoa/profiles/profile_signin_confirmation_view_controller.mm

 // Copyright 2014 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.
 
 #import "chrome/browser/ui/cocoa/profiles/profile_signin_confirmation_view_controller.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <cmath>
@@ skipping 391 matching lines @@
     delegate_->OnSigninWithNewProfile();
     delegate_ = NULL;
     closeDialogCallback_.Run();
   }
 }
 
 - (void)learnMore {
   chrome::NavigateParams params(
       browser_, GURL(chrome::kChromeEnterpriseSignInLearnMoreURL),
       ui::PAGE_TRANSITION_AUTO_TOPLEVEL);
-  params.disposition = NEW_POPUP;
+  params.disposition = WindowOpenDisposition::NEW_POPUP;
   params.window_action = chrome::NavigateParams::SHOW_WINDOW;
   chrome::Navigate(&params);
 }
 
 - (BOOL)textView:(NSTextView*)textView
    clickedOnLink:(id)link
          atIndex:(NSUInteger)charIndex {
   if (textView == explanationField_.get()) {
     [self learnMore];
     return YES;
@@ skipping 26 matching lines @@
 
 - (NSButton*)createProfileButton {
   return createProfileButton_.get();
 }
 
 - (NSTextView*)explanationField {
   return explanationField_.get();
 }
 
 @end