This CL removes an invalid CSS property value and replaces it with the initial value.

chrome/browser/resources/ntp4/tile_page.css

 /* Copyright (c) 2012 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. */
 
 .tile-page {
   -webkit-box-orient: vertical;
   display: -webkit-box;
   height: 100%;
   position: relative;
   width: 100%;
@@ skipping 143 matching lines @@
     -webkit-transform: scale(1, 1);
   }
 
   60% {
     -webkit-animation-timing-function: ease-in;
     -webkit-transform: scale(1.3, 0.02);
     opacity: 1;
   }
 
   90% {
-    -webkit-animation-timing-function: default;
     -webkit-transform: scale(0.3, 0.02);
     opacity: 0.7;
   }
 
   100% {
     -webkit-animation-timing-function: linear;
     -webkit-transform: scale(0.3, 0.02);
     opacity: 0;
   }
 }
@@ skipping 10 matching lines @@
 
 /** Scrollbars ****************************************************************/
 
 .tile-page-content::-webkit-scrollbar {
   width: 13px;
 }
 
 .tile-page-content::-webkit-scrollbar-button {
   display: none;
 }