ntp: fix most visited close button

chrome/browser/resources/ntp4/most_visited_page.css

 /* Copyright (c) 2011 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.
  */
 
 .most-visited {
   position: absolute;
 }
 
 .most-visited {
@@ skipping 38 matching lines @@
 html[dir=rtl] .most-visited .close-button {
   left: 0;
   right: auto;
 }
 
 .most-visited:hover .close-button {
   opacity: 1;
   -webkit-transition-delay: 0.5s;
 }
 
-.close-button:hover {
-  -webkit-transition-delay: 0;
+.most-visited .close-button:hover {
+  -webkit-transition: none;
 }
 
 .most-visited .favicon {
   background: no-repeat 5px 50%;
   bottom: 7px;
   box-sizing: border-box;
   display: block;
   height: 16px;
   position: absolute;
   width: 100%;
@@ skipping 89 matching lines @@
  * Override opacity of the tile to 1, so that the new tile animation
  * occurs simultaneously with the trash animation. */
 .tile.dragging.finishing-drag {
   opacity: 1;
 }
 
 /* Don't display the new tile until there's something to show.  */
 .blacklisted {
   opacity: 0;
 }