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

chrome/browser/resources/contextual_search/promo.css

Index: chrome/browser/resources/contextual_search/promo.css
diff --git a/chrome/browser/resources/contextual_search/promo.css b/chrome/browser/resources/contextual_search/promo.css
index 3fd54966481cc1c3ff5175a8d37e64ea3a8bbf0c..2b409a179a24c6b2a7531ca33abb394f1c035219 100644
--- a/chrome/browser/resources/contextual_search/promo.css
+++ b/chrome/browser/resources/contextual_search/promo.css
@@ -46,3 +46,10 @@ a {
   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;
+}