Add a new App launcher promo to the apps page / NTP.

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;
+  font-family: Arial, Helvetica, sans-serif;
+  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;
+}