Remove the app launcher promo code

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 81 matching lines @@
   cursor: pointer;
 }
 
 .app-img-container > img:first-child {
   display: block;
 }
 
 .app .invisible {
   visibility: hidden;
 }
-
-#app-launcher-promo {
-  background-color: white;
-  border: 1px solid lightgray;
-  border-bottom-width: 3px;
-  border-radius: 2px;
-  border-top-width: 2px;
-  bottom: 90px;
-  height: 120px;
-  left: 50%;
-  margin-left: -300px;
-  position: fixed;
-  width: 600px;
-}
-
-#app-launcher-promo > .close-button {
-  position: absolute;
-  right: 10px;
-  top: 10px;
-  width: 14px;
-}
-
-.apps-promo-text {
-  color: #222;
-  font-size: 16px;
-  left: 30px;
-  line-height: 24px;
-  position: absolute;
-  top: 30px;
-}
-
-.apps-promo-learn-more {
-  background-color: rgb(77, 144, 254);
-  border: 1px solid rgb(47, 91, 183);
-  border-radius: 2px;
-  color: white;
-  cursor: default;
-  font-size: 11px;
-  font-weight: bold;
-  height: 27px;
-  left: 30px;
-  line-height: 27px;
-  padding: 0 8px;
-  position: absolute;
-  text-align: center;
-  text-decoration: none;
-  top: 70px;
-  width: 90px;
-}
-
-.apps-promo-learn-more:hover {
-  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;
-}