[Search] Make the text swoosh away off the screen when the user taps the opt-in link.

chrome/browser/resources/contextual_search/promo.css

 /* Copyright 2014 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.
 */
 @font-face {
   font-family: 'Roboto2';
   font-weight: 400;
   src: local('Roboto'), local('Roboto2-Regular'),
       url(/roboto.woff2) format('woff2'), url(/roboto.woff) format('woff');
 }
@@ skipping 28 matching lines @@
   text-decoration: none;
   text-transform: uppercase;
 }
 
 #button-container {
   position: fixed;
   text-align: right;
   top: calc(70% - 76px /* action bar */ - 69px /* height of content */);
   width: 100%;
 }
+
+#container.hide {
+  -webkit-transform: scale(0.95);
+  -webkit-transition-property: opacity, -webkit-transform;
+  -webkit-transition-duration: 218ms;
+  opacity: 0;
+}