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

chrome/browser/resources/contextual_search/promo.js

Index: chrome/browser/resources/contextual_search/promo.js
diff --git a/chrome/browser/resources/contextual_search/promo.js b/chrome/browser/resources/contextual_search/promo.js
index 516822f5e091ab820a4da1e692dfa2a537f0e80a..dfdf1eff11cb81ffa5a248ceddd33a42f15a5157 100644
--- a/chrome/browser/resources/contextual_search/promo.js
+++ b/chrome/browser/resources/contextual_search/promo.js
@@ -1,5 +1,14 @@
 /* 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.
-   TODO(mathp): Add some JS here.
 */
+
+/**
+ * On load, registers the handler to add the 'hide' class to the container
+ * element in order to hide it.
+ */
+window.onload = function() {
+  $('optin-label').addEventListener('click', function() {
+    $('container').classList.add('hide');
+  });
+};