NTP4: Remove overflow from .tile-grid to fix app clipping issue.

chrome/browser/resources/ntp4/tile_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.
  */
 
 .tile-page {
   display: -webkit-box;
   height: 100%;
   position: relative;
   width: 100%;
@@ skipping 26 matching lines @@
   box-sizing: border-box;
   /* Scrollbar width(13px) + balance right padding.  */
   padding-left: 93px;
   padding-right: 80px;
   -webkit-box-flex: 1;
   /* Don't apply clip mask to padding. */
   -webkit-mask-clip: content-box;
 }
 
 .tile-grid {
-  overflow: hidden;
   position: relative;
   width: 100%;
 }
 
 .tile {
   display: inline-block;
   position: absolute;
   -webkit-print-color-adjust: exact;
   /* Don't offer the context menu on long-press. */
   -webkit-touch-callout: none;
@@ skipping 105 matching lines @@
 
 /** Scrollbars ****************************************************************/
 
 .tile-page-content::-webkit-scrollbar {
   width: 13px;
 }
 
 .tile-page-content::-webkit-scrollbar-button {
   display: none;
 }