Verify replacement and activation behavior for notifications on Android.

chrome/test/data/notifications/android_test_worker.js

Index: chrome/test/data/notifications/android_test_worker.js
diff --git a/chrome/test/data/notifications/android_test_worker.js b/chrome/test/data/notifications/android_test_worker.js
index 421494a6e3dfb14beca28c2ecfc25fba715930b8..f2a2de5e2f377dd465497b63aeca02993f073a24 100644
--- a/chrome/test/data/notifications/android_test_worker.js
+++ b/chrome/test/data/notifications/android_test_worker.js
@@ -8,3 +8,7 @@ addEventListener('message', function(event) {
   messagePort = event.data;
   messagePort.postMessage('ready');
 });
+
+addEventListener('notificationclick', function(event) {
+  event.notification.close();
+});