[Background Fetch] Throw DOMException for responseReady on abort.

According to the spec, responseReady in BackgroundFetchRecord should
throw an AbortError DOMException if the fetch was abandoned.

https://wicg.github.io/background-fetch/#create-record-objects (2.4.3)

Change-Id: Ieadf278acd061e05b8822014d0934f050fcac702

background-fetch/abort.https.window.js

@@ -56,4 +56,16 @@ backgroundFetchTest(async (test, backgroundFetch) => {
     };
   });
 
-}, 'Calling BackgroundFetchRegistration.abort sets the correct fields and responses are still available');
+}, 'Calling BackgroundFetchRegistration.abort sets the correct fields and responses are still available');
+
+backgroundFetchTest(async (test, backgroundFetch) => {
+  const registration = await backgroundFetch.fetch(
+      uniqueId(), '/serviceworker/resources/slow-response.php');
+  assert_true(await registration.abort());
+
+  const {results} = await getMessageFromServiceWorker();
+  assert_equals(results.length, 1);
+  assert_false(results[0].response);
+  assert_equals(results[0].name, 'AbortError');
+
+}, 'An aborted fetch throws a DOM exception when accessing an incomplete record', 'sw-abort.js');

background-fetch/service_workers/sw-abort.js

@@ -0,0 +1,23 @@
+importScripts('sw-helpers.js');
+
+async function getFetchResult(record) {
+  try {
+    await record.responseReady;
+  } catch (e) {
+    return {
+      response: false,
+      name: e.name,
+    };
+  }
+
+  return {
+    response: true,
+  };
+}
+self.addEventListener('backgroundfetchabort', event => {
+  event.waitUntil(
+    event.registration.matchAll()
+      .then(records =>
+            Promise.all(records.map(record => getFetchResult(record))))
+      .then(results => sendMessageToDocument({results})));
+});

background-fetch/service_workers/sw.js

@@ -13,7 +13,7 @@ async function getFetchResult(record) {
   };
 }
 
-function handleBackgroundFetchUpdateEvent(event) {
+function handleBackgroundFetchEvent(event) {
   event.waitUntil(
     event.registration.matchAll()
       .then(records =>
@@ -25,6 +25,6 @@ function handleBackgroundFetchUpdateEvent(event) {
       }));
 }
 
-self.addEventListener('backgroundfetchsuccess', handleBackgroundFetchUpdateEvent);
-self.addEventListener('backgroundfetchfail', handleBackgroundFetchUpdateEvent);
-self.addEventListener('backgroundfetchabort', handleBackgroundFetchUpdateEvent);
+self.addEventListener('backgroundfetchsuccess', handleBackgroundFetchEvent);
+self.addEventListener('backgroundfetchfail', handleBackgroundFetchEvent);
+self.addEventListener('backgroundfetchabort', handleBackgroundFetchEvent);