[Fetch API] Request's JS wrapper should be kept alive in FetchEvent

third_party/WebKit/LayoutTests/http/tests/serviceworker/chromium/resources/fetch-request-with-gc.js

+function wait(delay) {
+  return new Promise(res => {
+     setTimeout(res, delay);
+  });

[falken, 2016/06/02 08:36:32]

indent an additional two
(or make the whole thing one line without braces?) 

slightly prefer resolve instead of res, since res reminds me of response.

[yhirano, 2016/06/02 10:10:11]

Done.

+}
+
+self.addEventListener('fetch', e => {
+    self.gc();
+    e.respondWith(wait(10).then(() => {
+        self.gc();
+        return fetch(e.request);
+      }));
+  });