Tests that notification resource requests are handled by onfetch.

third_party/WebKit/LayoutTests/http/tests/notifications/resources/test-helpers.js

Index: third_party/WebKit/LayoutTests/http/tests/notifications/resources/test-helpers.js
diff --git a/third_party/WebKit/LayoutTests/http/tests/notifications/resources/test-helpers.js b/third_party/WebKit/LayoutTests/http/tests/notifications/resources/test-helpers.js
index d9fb5a297c918da802fdda4a481b347cbe25e9b5..3bbb2217bbc1bf7bdaacff04ca894ed30050229b 100644
--- a/third_party/WebKit/LayoutTests/http/tests/notifications/resources/test-helpers.js
+++ b/third_party/WebKit/LayoutTests/http/tests/notifications/resources/test-helpers.js
@@ -101,3 +101,13 @@ function simulateNotificationClick(title, actionIndex, port)
         });
     });
 }
+
+function listenOnce(target, type)

[Peter Beverloo, 2016/04/21 17:27:00]

++docs

[Michael van Ouwerkerk, 2016/04/22 13:24:09]

Done.

+{
+    return new Promise((resolve, reject) => {
+        target.addEventListener(type, function listener(event) {
+            target.removeEventListener(type, listener);
+            resolve(event);
+        });
+    });
+}