Make some updates to extension iconography.

chrome/browser/resources/ntp4/apps_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. */
 
 .app {
   outline: none;
   position: absolute;
   text-align: center;
 }
 
@@ skipping 47 matching lines @@
   vertical-align: middle;
   z-index: 0;
 }
 
 .app-icon-div .app-img-container {
   bottom: 10px;
   left: 10px;
   position: absolute;
 }
 
-.app-icon-div .color-stripe {
-  border-bottom-left-radius: 5px 5px;
-  border-bottom-right-radius: 5px 5px;
-  bottom: 0;
-  height: 3px;
-  opacity: 1.0;
-  position: absolute;
-  width: 100%;
-  z-index: 100;
-}
-
 .app-context-menu > button:first-child {
   font-weight: bold;
 }
 
 .app-context-menu {
   z-index: 1000;
 }
 
 .app-context-menu > [checked]::before {
   height: 5px;
@@ skipping 64 matching lines @@
   background-image: -webkit-linear-gradient(
       top, rgb(77, 144, 254), rgb(53, 122, 232));
   border: 1px solid rgb(47, 91, 183);
 }
 
 #app-launcher-promo > img {
   bottom: 0;
   position: absolute;
   right: 30px;
 }