DOMUI Prefs: Fix close buttons

The recent style change added another class to the buttons, exposing this latent bug.

BUG=None
TEST=Clicking the delete button in a DOMUI prefs list should delete the item.

Review URL: http://codereview.chromium.org/6372005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@71886 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/resources/options/deletable_item_list.js

@@ -121,7 +121,7 @@ cr.define('options', function() {
         return;
 
       var target = e.target;
-      if (target.className == 'close-button') {
+      if (target.classList.contains('close-button')) {
         var listItem = this.getListItemAncestor(target);
         var selected = this.selectionModel.selectedIndexes;